Importance of the Immune System Quiz
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Questions and Answers

Why is the immune system considered vital for survival?

  • To trigger allergies and autoimmunity
  • To protect against infectious pathogens and cancer development (correct)
  • To increase the incidence of certain cancers
  • To cause tissue injury and disease

    • What can happen when individuals have immune deficiencies?

  • Increased susceptibility to infections and certain cancers (correct)
  • Increased resistance to infections
  • Enhanced immune responses
  • Decreased incidence of certain cancers

    • Which of the following is an example of a disorder caused by immune responses?

  • Allergies (correct)
  • Heart disease
  • Muscle atrophy
  • Diabetes

    • What type of diseases are discussed in the chapter related to immunologic reactivity?

    <p>Diseases caused by too little or too much immunologic reactivity, and diabetes</p> Signup and view all the answers

    In which disease is an abnormal protein, sometimes derived from immunoglobulins, deposited in tissues?

    <p>Amyloidosis</p> Signup and view all the answers

    What is the main characteristic that distinguishes innate immunity from adaptive immunity?

    <p>Speed of response</p> Signup and view all the answers

    Which type of immunity is conventionally referred to as the immune response?

    <p>Acquired immunity</p> Signup and view all the answers

    Which component of the immune system provides immediate defense against microbes and damaged cells?

    <p>Innate immunity</p> Signup and view all the answers

    What type of antigens does autoimmunity typically target?

    <p>Self antigens</p> Signup and view all the answers

    Which immunity category involves mechanisms that adapt to exposure to foreign substances?

    <p>Acquired immunity</p> Signup and view all the answers

    What term describes the immediate protective host reactions induced by innate immunity?

    <p>Rapid innate response</p> Signup and view all the answers

    Which immunity type is considered the first line of defense against infectious pathogens?

    <p>Innate immunity</p> Signup and view all the answers

    Which term refers to the intrinsic mechanisms that react immediately to provide defense?

    <p><strong>Innate immunity</strong></p> Signup and view all the answers

    Which cells are primarily responsible for phagocytosing invaders in the blood?

    <p>Monocytes</p> Signup and view all the answers

    What is the main function of tissue-resident macrophages like Kupffer cells in the liver?

    <p>Destroy invading microbes</p> Signup and view all the answers

    Which plasma proteins are involved in the innate immune response and can be found in the complement system?

    <p>Complement proteins</p> Signup and view all the answers

    What is the role of dendritic cells in the immune system?

    <p>Activate T cells</p> Signup and view all the answers

    Which type of cells produce antimicrobial molecules like defensins in the body?

    <p>Epithelial cells</p> Signup and view all the answers

    What is the origin of some tissue-resident macrophages like microglia in the brain?

    <p>Yolk sac or fetal liver</p> Signup and view all the answers

    Innate lymphoid cells contribute to innate immunity by primarily functioning as:

    <p>Secretory cells</p> Signup and view all the answers

    Which type of barrier plays a vital role in preventing microbial entry into the body?

    <p>'Epithelial' barrier</p> Signup and view all the answers

    What is the primary function of dendritic cells?

    <p>Recognizing antigens and presenting peptides to T lymphocytes</p> Signup and view all the answers

    How do dendritic cells differ from macrophages?

    <p>Dendritic cells are not involved in destruction of offending agents</p> Signup and view all the answers

    What is the role of cytokines secreted by dendritic cells?

    <p>Initiating inflammation</p> Signup and view all the answers

    What distinguishes innate lymphoid cells (ILCs) from T lymphocytes?

    <p>Presence of T-cell antigen receptors</p> Signup and view all the answers

    Which immune cells serve as sentinels that detect danger and initiate innate immune responses?

    <p>Dendritic cells</p> Signup and view all the answers

    What is the main function of natural killer (NK) cells in immunity?

    <p>Destroying infected host cells</p> Signup and view all the answers

    Which cell type plays a crucial role in innate immunity by activating other immune cells through the production of inflammatory cytokines?

    <p>Mast cells</p> Signup and view all the answers

    Which plasma protein is involved in innate immunity and coats microbes to promote phagocytosis?

    <p>C-reactive protein</p> Signup and view all the answers

    Which pathway of the complement system may be activated by antibody-antigen complexes during adaptive immune responses?

    <p>Classical pathway</p> Signup and view all the answers

    Which cell type provides protection against intracellular bacteria and viruses, serving as a first line of defense in innate immunity?

    <p>Natural killer cells</p> Signup and view all the answers

    What is the main function of lung surfactant in innate immunity?

    <p>Providing protection against inhaled microbes</p> Signup and view all the answers

    Which group of T cells is responsible for producing inflammatory cytokines and is essential in the early phases of immune reactions?

    <p>Th1</p> Signup and view all the answers

    Which circulating protein plays a role in innate immunity by promoting phagocytosis through coating microbes?

    <p>Tumor necrosis factor</p> Signup and view all the answers

    Which cell type is capable of reacting to microbes and producing mediators of inflammation, playing a role in innate immunity?

    <p>Tissue-resident macrophages</p> Signup and view all the answers

    Which mechanism is involved in complement activation through the alternative pathway during innate immune responses?

    <p>Microbe activation</p> Signup and view all the answers

    What is the primary function of mannose-binding lectin in the innate immune response?

    <p>Coating microbes for phagocytosis</p> Signup and view all the answers

    What structures are recognized by cellular receptors participating in innate immunity?

    <p>Pathogen-associated molecular patterns</p> Signup and view all the answers

    Which family of receptors includes the Toll-like receptors (TLRs) that are essential for host defense against microbes?

    <p>Pattern recognition receptors</p> Signup and view all the answers

    Where are the Toll-like receptors (TLRs) located within cells?

    <p>Plasma membrane and endosomal vesicles</p> Signup and view all the answers

    What is the function of NOD-like receptors (NLRs) in the immune response?

    <p>Detect a variety of substances including those from damaged cells</p> Signup and view all the answers

    Which protein is activated by the inflammasome to generate the biologically active form of interleukin-1 (IL-1)?

    <p>Caspase-1</p> Signup and view all the answers

    What type of mutations in NLRs can result in periodic fever syndromes called autoinflammatory syndromes?

    <p>Gain-of-function mutations</p> Signup and view all the answers

    Which transcription factors are activated by Toll-like receptors to stimulate cytokine synthesis and adhesion molecules expression?

    <p>NF-KB and IREs</p> Signup and view all the answers

    What do pattern recognition receptors detect within cells?

    <p>Foreign substances</p> Signup and view all the answers

    What is the main function of the inflammasome in the immune response?

    <p>Generate the biologically active form of interleukin-1 (IL-1)</p> Signup and view all the answers

    Which molecules are recognized by NOD-like receptors (NLRs) as signs of danger or damage?

    <p>Products from necrotic or damaged cells</p> Signup and view all the answers

    What is the main function of STING pathway activation?

    <p>Producing antiviral cytokines</p> Signup and view all the answers

    Which receptor enables neutrophils to detect bacterial proteins?

    <p>G protein-coupled receptors</p> Signup and view all the answers

    What is the role of antibody-dependent cellular cytotoxicity (ADCC) mediated by NK cells?

    <p>Recognizing and destroying abnormal cells coated with IgG</p> Signup and view all the answers

    How do NK cell inhibitory receptors contribute to immune function?

    <p>Preventing NK cells from attacking normal cells</p> Signup and view all the answers

    Which cytokine activates macrophages to destroy ingested microbes?

    <p>Interferon-y (IFN-y)</p> Signup and view all the answers

    What triggers the vascular and cellular components of inflammation during innate immune reactions?

    <p>Cytokines and mediators</p> Signup and view all the answers

    How do Natural Killer (NK) cells contribute to early defense against intracellular microbial infections?

    <p>By secreting interferon-gamma (IFN-g)</p> Signup and view all the answers

    What is the primary function of IL-12 in the immune response?

    <p>Activating killing of target cells</p> Signup and view all the answers

    What is the main mechanism by which NK cells engage abnormal or infected cells?

    <p>Using activating and inhibitory receptors</p> Signup and view all the answers

    How do mannose receptors contribute to innate immunity?

    <p>Inducing phagocytosis of microbes</p> Signup and view all the answers

    What is the enzyme that is converted from an inactive to an active form in the inflammasome pathway?

    <p>Caspase-I</p> Signup and view all the answers

    Which protein complex recognizes products of dead cells and some microbes to induce the secretion of interleukin I?

    <p>NLRP3</p> Signup and view all the answers

    In the inflammasome pathway, what role does the adapter play?

    <p>Acting as a bridge between the sensor protein and caspase-I</p> Signup and view all the answers

    Which cellular receptor family participates in recognizing urate crystals, lipids, and cholesterol crystals in various inflammatory conditions?

    <p>NLRs</p> Signup and view all the answers

    What is the main outcome of the inflammasome pathway activation in response to urate crystals during gout inflammation?

    <p>Induction of interleukin I secretion</p> Signup and view all the answers

    Which type of inflammation is associated with obesity-related type 2 diabetes and atherosclerosis due to abnormal deposition of cholesterol crystals?

    <p>Obesity-associated inflammation</p> Signup and view all the answers

    Which class of receptors are responsible for detecting fungal glycans and eliciting inflammatory reactions to fungi on macrophages and dendritic cells?

    <p>C-type lectin receptors (CLRs)</p> Signup and view all the answers

    What happens when infected or stressed cells reduce class I MHC expression?

    <p>Inhibitory receptors are not engaged, and activating receptors are expressed.</p> Signup and view all the answers

    How do NK cells respond to healthy cells expressing ligands for activating receptors?

    <p>They remain inactive due to the engagement of inhibitory receptors.</p> Signup and view all the answers

    What is the primary function of inhibitory receptors in NK cells' interactions with healthy cells?

    <p>To ensure NK cells do not attack normal cells</p> Signup and view all the answers

    How do NK cells contribute to defense against virus-infected cells?

    <p>By directly killing infected cells</p> Signup and view all the answers

    What distinguishes innate immunity from adaptive immunity in terms of memory?

    <p>Adaptive immunity has memory, while innate immunity does not.</p> Signup and view all the answers

    How many different receptors does innate immunity use to recognize molecular patterns?

    <p>100</p> Signup and view all the answers

    What is the result of reduced class I MHC expression in infected or stressed cells?

    <p>Activation of NK cells</p> Signup and view all the answers

    Which type of immunity lacks memory or fine antigen specificity?

    <p>Innate immunity</p> Signup and view all the answers

    What stimulates the more powerful adaptive immune response following innate immunity's defense functions?

    <p>Danger signals produced by innate immunity</p> Signup and view all the answers

    How do inhibitory receptors help in preventing NK cells from attacking normal cells?

    <p>They ensure that inhibitory signals override activating signals</p> Signup and view all the answers

    What is the role of humoral immunity in the adaptive immune system?

    <p>Protects against extracellular microbes and their toxins</p> Signup and view all the answers

    What is the key feature that differentiates effector cells from memory cells in adaptive immunity?

    <p>Effector cells perform the function of eliminating microbes</p> Signup and view all the answers

    What term describes lymphocytes that have not encountered the specific antigen they are programmed to attack?

    <p>Naïve cells</p> Signup and view all the answers

    How do B lymphocytes contribute to adaptive immunity?

    <p>Secrete antibodies</p> Signup and view all the answers

    What is the main function of cellular immunity in the adaptive immune system?

    <p>Defense against intracellular microbes</p> Signup and view all the answers

    What is the process called when lymphocytes differentiate into effector and memory cells upon antigen recognition?

    <p>Clonal selection</p> Signup and view all the answers

    Which immune cells express highly diverse receptors to recognize a wide variety of foreign substances?

    <p><strong>T</strong> lymphocytes</p> Signup and view all the answers

    How do lymphocytes of adaptive immunity interact with one another in lymphoid organs?

    <p><strong>Anatomically segregate</strong> until activated by antigens</p> Signup and view all the answers

    What is the primary mediator of humoral immunity? (in terms of secreted products)

    <p><strong>Antibodies</strong></p> Signup and view all the answers

    What enzyme mediates recombination of gene segments in developing lymphocytes to generate antigen receptor diversity?

    <p>RAG-1 and RAG-2</p> Signup and view all the answers

    Where does DNA sequence variation occur during the assembly of gene segments in lymphocyte maturation?

    <p>At sites where the gene segments are joined</p> Signup and view all the answers

    Which cells contain recombined antigen receptor genes that result from somatic recombination?

    <p>T and B cells</p> Signup and view all the answers

    What is the outcome of inherited defects in RAG proteins regarding lymphocyte development?

    <p>Failure to generate mature lymphocytes</p> Signup and view all the answers

    In which regions of the antigen receptors do diverse amino acid sequences occur due to recombination of gene segments?

    <p>Variable regions</p> Signup and view all the answers

    Which cells contain recombined genes encoding TCR in T cells and Ig in B cells, leading to diverse antigen receptor generation?

    <p>T and B cells</p> Signup and view all the answers

    What is the enzyme product that facilitates the recombination of gene segments in developing lymphocytes?

    <p>RAG-1 and RAG-2</p> Signup and view all the answers

    How can polyclonal (nonneoplastic) lymphocyte proliferations be distinguished from monoclonal (neoplastic) lymphoid tumors?

    <p>By assessing the diversity of antigen receptor rearrangements within a population of lymphocytes.</p> Signup and view all the answers

    What is the role of Helper T lymphocytes in the immune system?

    <p>Activating other immune cells to destroy microbes</p> Signup and view all the answers

    What distinguishes polyclonal (nonneoplastic) lymphocyte proliferations from monoclonal (neoplastic) lymphoid tumors?

    <p>Unique DNA rearrangement in each T or B cell</p> Signup and view all the answers

    How are assays that assess the clonality of antigen receptor gene rearrangements helpful in diagnosing lymphoid neoplasms?

    <p>By distinguishing monoclonal from polyclonal lymphocyte proliferations</p> Signup and view all the answers

    What is the function of cytotoxic (killer) T lymphocytes (CTLs) in the immune system?

    <p>Killing infected cells</p> Signup and view all the answers

    Which gene rearrangements can differentiate nonneoplastic from neoplastic lymphoid cells?

    <p>$TCR$ or $Ig$ gene rearrangements</p> Signup and view all the answers

    In diagnosing lymphoid neoplasms, what is the significance of unique DNA rearrangements in each T or B cell and its progeny?

    <p>$TCR$ or $Ig$ gene rearrangements detection</p> Signup and view all the answers

    How do T lymphocytes recognize specific antigens?

    <p>By binding to MHC molecules</p> Signup and view all the answers

    What is the role of the CD3 and δ proteins in T cells?

    <p>Form the TCR complex</p> Signup and view all the answers

    What is the significance of MHC restriction in the immune system?

    <p>It ensures T cells only recognize cell-associated antigens</p> Signup and view all the answers

    How many polypeptide chains are noncovalently linked to each T cell receptor (TCR)?

    <p>Six</p> Signup and view all the answers

    Which region of the αβ TCR is responsible for binding to specific antigens?

    <p>Variable region</p> Signup and view all the answers

    What is the main function of regulatory lymphocytes?

    <p>To limit immune responses</p> Signup and view all the answers

    Where do T lymphocytes develop from precursors?

    <p>Thymus</p> Signup and view all the answers

    What is the composition of the TCR in approximately 95% of T cells?

    <p>$\alpha\beta$ polypeptide chain dimer</p> Signup and view all the answers

    What ensures that T cells only see cell-associated antigens?

    <p>MHC restriction</p> Signup and view all the answers

    Where do yδ T cells tend to aggregate?

    <p>Epithelial surfaces</p> Signup and view all the answers

    Which subset of T cells express markers found on NK cells?

    <p>NK-T cells</p> Signup and view all the answers

    What is the main function of CD8+ T cells?

    <p>Destroying host cells harboring microbes</p> Signup and view all the answers

    Which molecules initiate signals necessary for T cell activation?

    <p>CD4 and CD8</p> Signup and view all the answers

    What is the role of integrins in T-cell function?

    <p>Promoting attachment to APCs</p> Signup and view all the answers

    Which proteins are found on the surface of all mature, naive B cells?

    <p>IgM and IgD antibodies</p> Signup and view all the answers

    Which cells differentiate into plasma cells after stimulation by antigen?

    <p>β lymphocytes</p> Signup and view all the answers

    What is the estimated secretion rate of antibody molecules by a single plasma cell?

    <p>≥1000 molecules per second</p> Signup and view all the answers

    Which receptor complex is responsible for antigen recognition in B lymphocytes?

    <p>B-cell antigen receptor (BCR) complex</p> Signup and view all the answers

    Which immune cells are called sentinels for protecting against microbes trying to enter through epithelia?

    <p>γδ T cells</p> Signup and view all the answers

    What proteins are essential for signal transduction in response to antigen recognition in B cells?

    <p>Iga and Igß</p> Signup and view all the answers

    Which molecule is used by Epstein-Barr virus (EBV) as a receptor to enter and infect B cells?

    <p>CR2</p> Signup and view all the answers

    Which cells are the most important antigen-presenting cells for initiating T-cell responses against protein antigens?

    <p>Dendritic Cells (DCs)</p> Signup and view all the answers

    Where are dendritic cells located to capture antigens effectively?

    <p>Under epithelia and in the interstitia of tissues</p> Signup and view all the answers

    What feature of dendritic cells accounts for their key role in antigen presentation?

    <p>Expression of many receptors for capturing and responding to microbes</p> Signup and view all the answers

    What are immature dendritic cells called within the epidermis?

    <p>Langerhans cells</p> Signup and view all the answers

    What do interdigitating DCs resemble due to their numerous fine cytoplasmic processes?

    <p>Dendrites</p> Signup and view all the answers

    Which cells play a significant role in presenting antigens to naive T cells in lymphoid organs?

    <p>Follicular dendritic cells</p> Signup and view all the answers

    Which cell type is ideally located to present antigens to naive T cells in lymphoid organs?

    <p>Dendritic Cells</p> Signup and view all the answers

    What is the specific cell type that traps antigens bound to antibodies or complement proteins in germinal centers?

    <p>Follicular dendritic cells</p> Signup and view all the answers

    Which cell type plays a role in humoral immune responses by presenting antigens to B cells in the germinal center?

    <p>Follicular dendritic cells</p> Signup and view all the answers

    In which type of immunity do macrophages function as key effector cells for eliminating intracellular microbes?

    <p>Cell-mediated immunity</p> Signup and view all the answers

    Where do T cells primarily develop within the immune system?

    <p>Thymus</p> Signup and view all the answers

    Which of the following is a secondary lymphoid organ where adaptive immune responses occur?

    <p>Spleen</p> Signup and view all the answers

    What is the primary function of the spleen in immune responses?

    <p>Trapping and initiating adaptive immune responses to blood-borne antigens</p> Signup and view all the answers

    Where are cutaneous lymphoid systems located?

    <p>Under the epithelia of the skin</p> Signup and view all the answers

    What is the role of antigen-presenting cells in lymph nodes?

    <p>Initiating adaptive immune responses in lymph nodes</p> Signup and view all the answers

    What makes lymph nodes the site where the majority of adaptive immune responses occur?

    <p>Concentration of foreign antigens from tissues and epithelia</p> Signup and view all the answers

    What functions do dendritic cells perform in the immune response?

    <p>Present antigens to naive T cells in lymphoid organs</p> Signup and view all the answers

    Where is mucosal lymphoid tissue located?

    <p>Under the gastrointestinal and respiratory tracts' epithelium</p> Signup and view all the answers

    Where are the T lymphocytes concentrated in lymph nodes?

    <p>Paracortex</p> Signup and view all the answers

    What are the primary regions where immune responses are initiated in secondary lymphoid organs?

    <p>Paracortex</p> Signup and view all the answers

    Where do B cells primarily reside in the spleen?

    <p>Splenic white pulp</p> Signup and view all the answers

    What is the main function of follicular dendritic cells (FDCs) in lymph nodes?

    <p>Presenting antigens to B lymphocytes</p> Signup and view all the answers

    Where are effector lymphocytes required to migrate in response to infection?

    <p>Sites of infection and inflammation</p> Signup and view all the answers

    Which region of the spleen contains T lymphocytes surrounding arterioles?

    <p>Periarteriolar lymphoid sheaths</p> Signup and view all the answers

    What is the role of dendritic cells (DCs) in secondary lymphoid organs?

    <p>Presenting antigens to T lymphocytes</p> Signup and view all the answers

    What is the main function of the paracortex region in lymph nodes?

    <p>T lymphocyte concentration</p> Signup and view all the answers

    What component of secondary lymphoid organs contains germinal centers if there has been an antigen response?

    <p>Follicles</p> Signup and view all the answers

    In which region of the spleen do B cells mainly reside?

    <p>Splenic white pulp</p> Signup and view all the answers

    What is the main function of MHC molecules in adaptive immunity?

    <p>Displaying peptide fragments for T cell recognition</p> Signup and view all the answers

    Why are MHC molecules important in the context of autoimmune diseases?

    <p>They are linked to antigen recognition by T cells</p> Signup and view all the answers

    What term describes the characteristic of the HLA system having thousands of distinct gene alleles in humans?

    <p>Polymorphism</p> Signup and view all the answers

    Where are Class I MHC molecules primarily expressed?

    <p>On all nucleated cells</p> Signup and view all the answers

    What is the significance of MHC gene products being divided into two major classes?

    <p>It influences the type of immune cells interacting with antigens</p> Signup and view all the answers

    How does the polymorphism of the HLA system impact organ transplantation?

    <p>It presents a barrier due to allele diversity</p> Signup and view all the answers

    What is the primary reason for naming human MHC molecules as human leukocyte antigens (HLA)?

    <p>As they were initially detected on leukocytes</p> Signup and view all the answers

    What forms the cleft where peptides bind in class I MHC molecules?

    <p>01 and ds domains</p> Signup and view all the answers

    Which cells recognize peptides bound to class I MHC molecules?

    <p>CD8+ T cells</p> Signup and view all the answers

    Where are cytoplasmic proteins degraded to produce peptides that bind to class I MHC molecules?

    <p>Endoplasmic reticulum (ER)</p> Signup and view all the answers

    What is the role of 2-microglobulin in class I MHC molecules?

    <p>Linkage to heavy chains</p> Signup and view all the answers

    Which genes encode the a chains of class I MHC molecules?

    <p>HLA-A, HLA-B, HLA-C</p> Signup and view all the answers

    Which cells recognize peptides presented by class I MHC molecules?

    <p>CD8+ T cells</p> Signup and view all the answers

    What kind of antigens do class I MHC molecules present?

    <p>Virus- and tumor-specific antigens</p> Signup and view all the answers

    What is the function of the polymorphic amino acid residues in class I MCH molecules?

    <p>Base of peptide-binding groove</p> Signup and view all the answers

    Which proteins mediate communications between leukocytes according to the text?

    <p>Cytokines</p> Signup and view all the answers

    In innate immune responses, what do cytokines primarily function to induce?

    <p>Inflammation</p> Signup and view all the answers

    Which cells are the major sources of cytokines like TNF and IL-1 in innate immune responses?

    <p>Macrophages</p> Signup and view all the answers

    What is the primary function of most cytokines in terms of action on neighboring cells?

    <p>Paracrine actions</p> Signup and view all the answers

    Which immune cells produce cytokines principally in adaptive immune responses?

    <p>T lymphocytes</p> Signup and view all the answers

    What is the term used for the actions of cytokines on neighboring cells?

    <p>Paracrine</p> Signup and view all the answers

    Which type of cells can also produce cytokines in addition to macrophages and DCs?

    <p>Epithelial cells</p> Signup and view all the answers

    What effect do cytokines have on virus replication in innate immune responses?

    <p><strong>Inhibit</strong> replication</p> Signup and view all the answers

    Which group of molecules mediates communications between leukocytes?

    <p>Cytokines</p> Signup and view all the answers

    What is the main role of molecularly defined cytokines according to the text?

    <p>Mediate cell-to-cell communication</p> Signup and view all the answers

    What role do CD8+ T cells play in the immune system?

    <p>Killing of tumor cells and eliminating viruses</p> Signup and view all the answers

    How are CD8+ T cells restricted in their recognition of antigens?

    <p>They can only recognize peptides presented with class I MHC molecules</p> Signup and view all the answers

    What is the function of B-microglobulin in MHC class I molecules?

    <p>Acts as a coreceptor binding to CD8+ T cells</p> Signup and view all the answers

    What is the significance of the crystal structure of class II MHC molecules?

    <p>It demonstrates the presence of peptide-binding clefts facing outward</p> Signup and view all the answers

    Where are class II MHC molecules encoded?

    <p>In a region called HLA-DR</p> Signup and view all the answers

    What differentiates class I MHC-restricted CD8+ T cells from other T cell subsets?

    <p>They are involved in killing virus-infected and tumor cells</p> Signup and view all the answers

    What is the primary function of the CD8+ T cell receptor (TCR) in antigen recognition?

    <p>Recognizing the MHC-peptide complex on antigen-presenting cells</p> Signup and view all the answers

    How do CD8+ T cells interact with MHC-peptide complexes?

    <p>By recognizing both the MHC and peptide portions of the complex</p> Signup and view all the answers

    What is the significance of the HLA genes' polymorphism in the immune system?

    <p>Ensure individuals can display any microbial peptide for protection</p> Signup and view all the answers

    Why are grafts exchanged between individuals with different MHC profiles often rejected by the immune system?

    <p>Because they are considered foreign</p> Signup and view all the answers

    Which cells recognize antigens only in the context of self class II molecules?

    <p>CD4+ T cells</p> Signup and view all the answers

    What role do class II MHC molecules play in the immune response?

    <p>Present antigens to CD4+ T cells</p> Signup and view all the answers

    Why do siblings have a 1 in 4 chance of sharing the same MHC profile?

    <p>'Random' recognition mechanism</p> Signup and view all the answers

    Which region plays a crucial role in segregating cytoplasmic and internalized antigens for the appropriate immune response?

    <p>MHC molecules</p> Signup and view all the answers

    What is the primary function of CD4+ T cells in the immune system?

    <p>Regulate immune responses</p> Signup and view all the answers

    How do class II MHC molecules differ from class I MHC molecules in terms of antigen presentation?

    <p>'Intracellular' vs. 'Extracellular' antigen presentation</p> Signup and view all the answers

    'Helper cells' in the immune system primarily interact with which type of molecule on cell surfaces?

    <p>'Self' class II MHC molecules</p> Signup and view all the answers

    What type of immune response is mainly triggered by class II MHC molecules presenting antigens?

    <p>Th2 cell-mediated response against extracellular microbes</p> Signup and view all the answers

    What is the primary function of adjuvants given with a protein antigen during immunization?

    <p>To stimulate innate immune responses</p> Signup and view all the answers

    Which cells are responsible for carrying microbial antigens to draining lymph nodes?

    <p>Dendritic cells</p> Signup and view all the answers

    In the immune response to tumors and transplants, what may provide 'signal 2' for activating adaptive immunity?

    <p>Substances from necrotic cells</p> Signup and view all the answers

    Which cytokines are mainly responsible for promoting lymphocyte proliferation and differentiation?

    <p>IL-2 and IL-4</p> Signup and view all the answers

    Which molecules function cooperatively to activate antigen-specific lymphocytes during innate immune responses?

    <p>Costimulators and MHC molecules</p> Signup and view all the answers

    Which type of cytokines primarily serve to limit and terminate immune responses?

    <p>IL-10 and TGF-ß</p> Signup and view all the answers

    What is the main role of Br proteins (CD80 and CD86) in immune responses?

    <p>Provide costimulatory signals to T cells</p> Signup and view all the answers

    Which cells produce colony-stimulating factors (CSFs) to stimulate blood cell colony formation?

    <p>Marrow stromal cells, T lymphocytes, and macrophages</p> Signup and view all the answers

    Which receptors on innate immune cells recognize microbial antigens initially?

    <p>Pattern recognition receptors</p> Signup and view all the answers

    What practical therapeutic applications have been derived from knowledge about cytokines?

    <p>Inhibiting cytokine production for controlling inflammation</p> Signup and view all the answers

    During immune responses, what ensures that adaptive immunity is triggered by microbes and not harmless substances?

    <p>'Signal 2'</p> Signup and view all the answers

    Patients with rheumatoid arthritis often respond well to which type of therapy mentioned in the text?

    <p>TNF antagonists</p> Signup and view all the answers

    What is the first line of defense in immune responses that also activates adaptive immunity?

    <p>Pattern recognition receptors</p> Signup and view all the answers

    Which cells primarily produce GM-CSF and IL-3 among others?

    <p>T lymphocytes</p> Signup and view all the answers

    Which cells use membrane-bound antibody molecules to recognize various chemical types of antigens?

    <p>B lymphocytes</p> Signup and view all the answers

    What is the function of IL-10 in immune responses?

    <p>To limit and terminate immune responses</p> Signup and view all the answers

    'Signal 1' in immune responses refers to the recognition of antigens complexed with which molecules on the cell surface?

    <p>MHC molecules</p> Signup and view all the answers

    Which cytokines stimulate hematopoiesis?

    <p>GM-CSF and IL-3</p> Signup and view all the answers

    What is the result of inhibiting cytokine production or actions according to the text?

    <p>Control of harmful effects of inflammation</p> Signup and view all the answers

    Which group of cytokines is associated with promoting lymphocyte proliferation among others?

    <p>Interleukins (ILs)</p> Signup and view all the answers

    Which cells secrete the cytokine IFN-$ ext{γ}$, a potent macrophage activator?

    <p>Helper T cells</p> Signup and view all the answers

    What stimulates B cells to differentiate into IgE-secreting plasma cells?

    <p>IL-4</p> Signup and view all the answers

    During classical macrophage activation, which combination of factors results in the production of microbicidal substances?

    <p>CD40 and IFN-$ ext{γ}$</p> Signup and view all the answers

    Which cells bind to IgE-coated microbes like helminthic parasites to eliminate them?

    <p>Eosinophils</p> Signup and view all the answers

    Which cells induce the production of eosinophils in the marrow and activate eosinophils at immune response sites?

    <p>Th2 cells</p> Signup and view all the answers

    What is the main function of Th1 subset cells?

    <p>Secrete IFN-$ ext{γ}$</p> Signup and view all the answers

    Which molecules are engaged during the interaction where CD4+ helper T cells recognize antigens displayed by macrophages or B lymphocytes?

    <p>CD40L and CD40 receptor</p> Signup and view all the answers

    Which type of cells differentiate into effector cells that secrete distinct sets of cytokines and perform different functions?

    <p>Effector T cells</p> Signup and view all the answers

    What is the primary function of IL-5 secreted by Th2 cells?

    <p>Activate eosinophils at immune response sites</p> Signup and view all the answers

    Which cytokine is secreted by Thl subset cells, leading to the activation of macrophages?

    <p>IFN-$ ext{γ}$</p> Signup and view all the answers

    What is the main function of Th17 cells in the immune system?

    <p>Recruit neutrophils and monocytes to destroy extracellular bacteria and fungi</p> Signup and view all the answers

    What is the primary role of activated CD8+ T lymphocytes?

    <p>Destroy infected cells harboring microbes in the cytoplasm</p> Signup and view all the answers

    How do B lymphocytes respond upon activation?

    <p>Endocytose antigens and present peptides to helper T cells</p> Signup and view all the answers

    What is the main function of plasma cells derived from B lymphocytes?

    <p>Produce different classes of antibodies to eliminate extracellular microbes</p> Signup and view all the answers

    What is the role of CTLs in tumor immunity?

    <p>Kill tumor cells by recognizing tumor-specific antigens</p> Signup and view all the answers

    What is the significance of antibody responses to protein antigens being T-dependent?

    <p>Require T cell help for optimal antibody production</p> Signup and view all the answers

    What is the unique function of helper T cells in antibody responses?

    <p>Activate B cells by providing necessary signals and cytokines</p> Signup and view all the answers

    What distinguishes innate immunity from adaptive immunity in terms of memory?

    <p>Adaptive immunity has memory cells after exposure to antigens.</p> Signup and view all the answers

    How do NK cells primarily contribute to defense against virus-infected cells?

    <p>By directly killing infected cells.</p> Signup and view all the answers

    Where are the T lymphocytes concentrated in lymph nodes?

    <p>Paracortex region</p> Signup and view all the answers

    Which family of receptors includes Toll-like receptors (TLRs) essential for host defense against microbes?

    <p>Pattern recognition receptors</p> Signup and view all the answers

    What is the primary function of IL-5 secreted by Th2 cells?

    <p>Promote eosinophil production</p> Signup and view all the answers

    Where do B lymphocytes differentiate into IgE-secreting plasma cells?

    <p><strong>Bone marrow</strong></p> Signup and view all the answers

    What is the main outcome of the inflammasome pathway activation in response to urate crystals during gout inflammation?

    <p><strong>Release of inflammatory cytokines</strong></p> Signup and view all the answers

    DNA sequence variation occurs during the assembly of gene segments in which stage of lymphocyte maturation?

    <p><strong>B cell development</strong></p> Signup and view all the answers

    What type of immune response is characterized by the production of antibodies mainly of the IgM class?

    <p>T-independent</p> Signup and view all the answers

    Which process improves the quality of the humoral immune response by stimulating the production of antibodies with high affinities for antigens?

    <p>Affinity maturation</p> Signup and view all the answers

    What is the main outcome of T-dependent responses that is absent in T-independent responses?

    <p>Ig isotype switching</p> Signup and view all the answers

    Which cells secrete cytokines that work together to stimulate B cells in the immune response?

    <p>Helper T cells</p> Signup and view all the answers

    Which molecule induces the production of antibodies with different classes (isotypes) through helper T-cell actions?

    <p>CD40L</p> Signup and view all the answers

    What feature distinguishes T-dependent responses from T-independent responses in terms of antibody production?

    <p>Ig isotype switching</p> Signup and view all the answers

    Which process leads to the initiation of B-cell activation by engaging many antigen molecules on each B cell?

    <p>Epitope recognition</p> Signup and view all the answers

    What is the main characteristic that differentiates T-independent responses from T-dependent responses?

    <p>$IgM$ secretion</p> Signup and view all the answers

    'Isotype switching' and 'affinity maturation' are features primarily observed in which type of immune response?

    <p>$\text{Adaptive}$</p> Signup and view all the answers

    What is the primary function of T follicular helper (TrH) cells in the immune response?

    <p>Stimulate B lymphocytes in germinal centers</p> Signup and view all the answers

    Which antibody type is secreted from mucosal epithelia to neutralize microbes in respiratory and gastrointestinal tracts?

    <p>IgA</p> Signup and view all the answers

    Which antibodies activate the complement system by the classical pathway?

    <p>IgG</p> Signup and view all the answers

    What is the role of IgE antibodies in combating parasites?

    <p>Activate eosinophils to kill parasites</p> Signup and view all the answers

    Where do long-lived memory cells primarily reside in the body?

    <p>Bone marrow</p> Signup and view all the answers

    Which cells are responsible for continuously producing antibodies in the bone marrow over extended periods?

    <p>Plasma cells from germinal centers</p> Signup and view all the answers

    Why do long-lived memory cells respond faster and more effectively upon reexposure to antigens?

    <p>They carry diverse receptors for antigens</p> Signup and view all the answers

    What is the main function of dendritic cells in the immune system?

    <p>Recognize antigens and present them to lymphocytes</p> Signup and view all the answers

    What is the underlying cause suspected in many hypersensitivity diseases?

    <p>Normal regulation of immune responses</p> Signup and view all the answers

    Which type of genes have been implicated in the development of hypersensitivity diseases?

    <p>Both HLA and non-HLA genes</p> Signup and view all the answers

    What is the primary mechanism of tissue injury in hypersensitivity reactions?

    <p>Effector mechanisms of defense against pathogens</p> Signup and view all the answers

    Which cells are involved in causing tissue injury in hypersensitivity reactions?

    <p>Th2 cells, IgE antibodies, mast cells</p> Signup and view all the answers

    How can hypersensitivity reactions be classified?

    <p>By the underlying immunologic mechanism</p> Signup and view all the answers

    What is the cause of issues in hypersensitivity reactions?

    <p>Poorly controlled reactions</p> Signup and view all the answers

    Which group of diseases is associated with immune responses against environmental antigens?

    <p>Allergy</p> Signup and view all the answers

    What are the functions of CD4+T cells primarily mediated by?

    <p>Cytokines</p> Signup and view all the answers

    Which immune cells are responsible for killing virus-infected and tumor cells?

    <p>NK cells</p> Signup and view all the answers

    What do antibodies secreted by plasma cells primarily do?

    <p>Neutralize microbes</p> Signup and view all the answers

    In immunology, what term is used to describe the transfer of immunity to neonates through antibodies?

    <p>Passive immunity</p> Signup and view all the answers

    What is the term used to describe immune reactions that cause tissue injury?

    <p>Hypersensitivity reactions</p> Signup and view all the answers

    Which group of disorders is characterized by the failure of tolerance to self-antigens?

    <p>Autoimmune disorders</p> Signup and view all the answers

    Which type of diseases are caused by a defective immune system?

    <p>Immunodeficiency diseases</p> Signup and view all the answers

    What is the primary cause of tissue injury in cell-mediated immune disorders?

    <p>T lymphocytes</p> Signup and view all the answers

    Which type of hypersensitivity involves the binding of antigen to IgE on mast cells?

    <p>Type I hypersensitivity</p> Signup and view all the answers

    In immune complex-mediated disorders, where do antigen-antibody complexes deposit and induce inflammation?

    <p>In tissues</p> Signup and view all the answers

    What is the term for the leukocytes recruited in immune complex-mediated disorders that produce tissue damage through enzyme release and free radicals?

    <p>Neutrophils</p> Signup and view all the answers

    Which cells are responsible for causing tissue injury in immediate (Type I) hypersensitivity reactions?

    <p>Mast cells</p> Signup and view all the answers

    What is the primary outcome of antibody-mediated disorders (type II hypersensitivity)?

    <p>Tissue inflammation</p> Signup and view all the answers

    Which antibody type plays a role in injurious reactions by promoting phagocytosis or lysis of cells?

    <p>IgG</p> Signup and view all the answers

    What is the antigen-antibody interaction primarily responsible for in immune complex-mediated disorders?

    <p>Tissue inflammation</p> Signup and view all the answers

    Which type of hypersensitivity is characterized by the deposition of antigen-antibody complexes in tissues?

    <p>Type III hypersensitivity</p> Signup and view all the answers

    What is the main impact of immediate (Type I) hypersensitivity reactions on a sensitized individual?

    <p>Systemic reaction</p> Signup and view all the answers

    What is the primary role of IL-13 in type I hypersensitivity reactions?

    <p>Enhances IgE production and stimulates mucus secretion</p> Signup and view all the answers

    In type I hypersensitivity reactions, what is unique about the late-phase reaction compared to the immediate reaction?

    <p>It is characterized by tissue infiltration with various leukocytes</p> Signup and view all the answers

    What is the main function of Th2 cells in immediate hypersensitivity disorders?

    <p>Promoting inflammation</p> Signup and view all the answers

    Which cytokine is crucial for B cell class switching to IgE in type I hypersensitivity reactions?

    <p>Interleukin-4 (IL-4)</p> Signup and view all the answers

    What is the immediate reaction in type I hypersensitivity characterized by?

    <p>Vasodilation and vascular leakage</p> Signup and view all the answers

    Which cell type is a key effector in type I hypersensitivity reactions due to its involvement in tissue destruction?

    <p>Eosinophil</p> Signup and view all the answers

    Which of the following cytokines is NOT produced by Th2 cells as part of the type I hypersensitivity response?

    <p><strong>Interleukin-6 (IL-6)</strong></p> Signup and view all the answers

    What is the primary mechanism through which Th2 cells attract more Th2 cells and other leukocytes to the site of a hypersensitivity reaction?

    <p><strong>Secretion of chemokines</strong></p> Signup and view all the answers

    What is a characteristic feature of the late-phase reaction following immediate hypersensitivity disorders?

    <p>Tissue infiltration with eosinophils and neutrophils</p> Signup and view all the answers

    How do Th2 cells contribute to the development of allergic reactions?

    <p>By stimulating inflammation and IgE production</p> Signup and view all the answers

    Which cytokine is NOT typically produced by Th2 cells in type I hypersensitivity reactions?

    <p>Interferon-gamma (IFN-gamma)</p> Signup and view all the answers

    What is the primary function of mast cells in immediate hypersensitivity reactions?

    <p>Release of biologically active mediators</p> Signup and view all the answers

    Where are mast cells commonly found in tissues, contributing to local immediate hypersensitivity reactions?

    <p>Near small blood vessels and nerves</p> Signup and view all the answers

    What do mast cells contain in their cytoplasmic granules that contribute to immediate hypersensitivity reactions?

    <p>Acidic proteoglycans</p> Signup and view all the answers

    Which group is predictably most responsive to antagonists of Th2 cytokines like IL-4 and IL-5?

    <p>Th2-high individuals</p> Signup and view all the answers

    What type of responses do type 2 Ilcs in tissue initially provide before the development of Th2 responses?

    <p>Cytokine response to epithelia</p> Signup and view all the answers

    What triggers the activation of mast cells and basophils by binding to receptors on the cell membrane?

    <p>C5a and C3a</p> Signup and view all the answers

    What is the primary difference between mast cells and basophils?

    <p>Presence in tissues</p> Signup and view all the answers

    What term describes the process where multivalent antigens cross-link adjacent IgE antibodies on mast cells?

    <p>Antigen cross-linking</p> Signup and view all the answers

    Which of the following is NOT a mast cell secretagogue triggering their activation?

    <p>Thrombin</p> Signup and view all the answers

    What is the role of FceRI in mast cells and basophils?

    <p>Specific for the Fc portion of IgE</p> Signup and view all the answers

    Which physical stimuli can trigger the activation of mast cells?

    <p>Heat and cold</p> Signup and view all the answers

    What do mast cells release upon activation that is responsible for immediate hypersensitivity reactions?

    <p>Histamine</p> Signup and view all the answers

    What characteristic separates basophils from mast cells in terms of location?

    <p>Presence in tissues</p> Signup and view all the answers

    What do multivalent antigens do when they bind to adjacent IgE antibodies on mast cells?

    <p>Cross-link antibodies</p> Signup and view all the answers

    What type of molecules bind to receptors on mast cells to trigger their activation?

    <p>Complement components C5a and C3a</p> Signup and view all the answers

    Which mediator is NOT derived from arachidonic acid in mast cells?

    <p>Histamine</p> Signup and view all the answers

    What is the most abundant mediator produced in mast cells by the cyclooxygenase pathway?

    <p>Prostaglandin D</p> Signup and view all the answers

    Which cytokine amplifies the Th2 response in immediate hypersensitivity reactions?

    <p>IL-4</p> Signup and view all the answers

    What is the role of Platelet-activating factor (PAF) in immediate hypersensitivity reactions?

    <p>Leukocyte recruitment</p> Signup and view all the answers

    Which cell population is often abundant in the late-phase reaction of immediate hypersensitivity disorders?

    <p>Eosinophils</p> Signup and view all the answers

    What is a unique protein released by activated eosinophils that can damage tissues?

    <p>Major basic protein</p> Signup and view all the answers

    Which crystal found in eosinophils promotes inflammation and enhances Th2 responses?

    <p>Charcot-Leyden crystals</p> Signup and view all the answers

    'Late-phase reaction' in immediate hypersensitivity involves the recruitment of leukocytes that:

    <p>(a) Amplify and sustain the inflammatory response without additional exposure to antigens.</p> Signup and view all the answers

    What is the main function of cytokines like IL-1 and TNF produced by mast cells?

    <p>Promote leukocyte recruitment.</p> Signup and view all the answers

    What is the primary function of histamine released by mast cells?

    <p>Increasing vascular permeability</p> Signup and view all the answers

    Which enzyme found in mast cell granules contributes to tissue damage and generation of kinins?

    <p>Chymotrypsin</p> Signup and view all the answers

    Which class of mediators serves to package and store amines within mast cell granules?

    <p>Proteoglycans</p> Signup and view all the answers

    What is the parent compound that is converted to leukotrienes and prostaglandins during mast cell activation?

    <p>Arachidonic acid</p> Signup and view all the answers

    Which enzyme is responsible for converting membrane phospholipids to arachidonic acid during mast cell activation?

    <p>Phospholipase A2</p> Signup and view all the answers

    Which of the following is a function of neutral proteases like chymase found in mast cell granules?

    <p>Lead to tissue damage</p> Signup and view all the answers

    What is the role of heparin in mast cell granules?

    <p>Serve as an anticoagulant</p> Signup and view all the answers

    Which enzyme is activated during mast cell activation leading to the production of leukotrienes?

    <p>5-lipoxygenase</p> Signup and view all the answers

    What category do arachidonic acid-derived products belong to in mast cell granules?

    <p>Lipid mediators</p> Signup and view all the answers

    What is a major function of lipid mediators produced from arachidonic acid during mast cell activation?

    <p>Acting as pro-inflammatory agents</p> Signup and view all the answers

    What genetic factor determines susceptibility to immediate hypersensitivity reactions?

    <p>Atopy</p> Signup and view all the answers

    Which cytokines have genetic polymorphisms that may contribute to allergic reactions?

    <p>IL-3, IL-4, IL-5</p> Signup and view all the answers

    What is the role of broad-spectrum anti-inflammatory drugs in managing allergies?

    <p>Long-term suppression of allergic reactions</p> Signup and view all the answers

    What percentage of atopic individuals have a positive family history of allergies?

    <p>50%</p> Signup and view all the answers

    Which chromosome region shows linkage to polymorphisms affecting reactivity to certain allergens?

    <p>Chromosome 6</p> Signup and view all the answers

    What environmental factor is highlighted as an important predisposing factor for allergies?

    <p>Urban lifestyle</p> Signup and view all the answers

    In patients with asthma, what genes show linkage to polymorphisms affecting allergic reactions?

    <p>Genes for cytokines like IL-3 and GM-CSF</p> Signup and view all the answers

    'Atopic' individuals tend to have higher levels of which substance compared to the general population?

    <p>'Helper' T cells</p> Signup and view all the answers

    Which genetic factor is suggested to permit reactivity to certain allergens?

    <p>HLA alleles</p> Signup and view all the answers

    'Immediate hypersensitivity reactions are genetically determined' refers primarily to what characteristic?

    <p>'Susceptibility'</p> Signup and view all the answers

    What is the term used to describe the phenomenon where early childhood exposure to microbial antigens potentially prevents subsequent pathologic responses against common environmental allergens?

    <p>The hygiene hypothesis</p> Signup and view all the answers

    Which statement best describes the primary observation made about dogs, cats, and chimpanzees in relation to allergies in the provided text?

    <p>Environment plays a significant role in allergic disease development.</p> Signup and view all the answers

    What triggers bronchial asthma, an allergic lung disease, according to the text?

    <p>Nonimmune stimuli such as temperature variations</p> Signup and view all the answers

    Why have commercial airlines largely stopped serving peanuts or foods containing peanuts according to the text?

    <p>Due to the risk of severe allergic reactions to minute quantities of peanuts.</p> Signup and view all the answers

    What type of reactions affect about 10% to 20% of the population and involve localized responses to common environmental allergens?

    <p>Immediate hypersensitivity reactions</p> Signup and view all the answers

    In systemic anaphylaxis, what is characterized by vascular shock, widespread edema, and respiratory distress?

    <p>Laryngeal edema</p> Signup and view all the answers

    What can trigger anaphylaxis in sensitized individuals following exposure in the community setting?

    <p>Insect toxins like bee venom</p> Signup and view all the answers

    What is the primary risk associated with severe allergic reactions within minutes after exposure to allergens according to the text?

    <p>'Anaphylactic shock'</p> Signup and view all the answers

    'Local Immediate Hypersensitivity Reactions' involve localized responses to which of the following?

    <p>'Immediate reaction' environmental allergens</p> Signup and view all the answers

    'Systemic Anaphylaxis' may occur after administration of foreign proteins or exposure to food allergens, but primarily involves what type of response?

    <p>'Immediate Type I hypersensitivity'</p> Signup and view all the answers

    What is the primary responsibility of mediators in Type I hypersensitivity reactions?

    <p>Causing immediate vascular and smooth muscle reactions</p> Signup and view all the answers

    Which antibodies are recognized by phagocyte Fc receptors during phagocytosis in Type II hypersensitivity reactions?

    <p>IgG antibodies</p> Signup and view all the answers

    In Type II hypersensitivity reactions, which antibodies may be specific for exogenous antigens?

    <p>IgG antibodies</p> Signup and view all the answers

    What is the main cause of tissue injury in Type II hypersensitivity reactions?

    <p>Deposition of antibodies on cell surfaces</p> Signup and view all the answers

    Which phase of the reaction is responsible for the manifestation of inflammation in Type I hypersensitivity reactions?

    <p>Late-phase reaction</p> Signup and view all the answers

    What is the consequence of IgG antibodies being recognized by phagocyte Fc receptors?

    <p>Depletion of antibody-coated cells</p> Signup and view all the answers

    Which type of antibodies are involved in opsonization and phagocytosis in Type II hypersensitivity reactions?

    <p>IgG antibodies</p> Signup and view all the answers

    Which cells are primarily responsible for cell lysis in antibody-dependent cell-mediated cytotoxicity (ADCC)?

    <p>NK cells</p> Signup and view all the answers

    In which of the following situations does cell lysis proceed without phagocytosis?

    <p>Transfusion reactions</p> Signup and view all the answers

    What is the main contribution of antibody-dependent cell-mediated cytotoxicity (ADCC) to common hypersensitivity diseases according to the text?

    <p>Cell lysis</p> Signup and view all the answers

    In autoimmune hemolytic anemia, agranulocytosis, and thrombocytopenia, what do individuals produce antibodies against?

    <p>Their own blood cells</p> Signup and view all the answers

    What characterizes hemolytic disease of the fetus and newborn (erythroblastosis fetalis) regarding antigenic differences?

    <p>Antigenic difference between mother and fetus</p> Signup and view all the answers

    What causes destruction of fetal red cells in hemolytic disease of the fetus and newborn?

    <p><em>IgG</em> antibodies</p> Signup and view all the answers

    Certain drug reactions may generate new antigenic epitopes against which individuals react. What specifically causes the generation of these new epitopes?

    <p><em>Conformational changes</em> to antigens</p> Signup and view all the answers

    In which type of reaction does the drug bind to plasma membrane proteins on host cells leading to antibody production against the drug-protein complex?

    <p><em>Type II hypersensitivity</em></p> Signup and view all the answers

    What is the main mechanism responsible for tissue injury in some forms of glomerulonephritis and vascular rejection in organ grafts?

    <p>Antibody-mediated inflammation</p> Signup and view all the answers

    In which disorder do antibodies reactive with acetylcholine receptors in the motor end plates of skeletal muscles block neuromuscular transmission?

    <p>Myasthenia gravis</p> Signup and view all the answers

    Which substances released by leukocytes during activation can damage tissues by digesting basement membrane, collagen, elastin, and cartilage?

    <p>Lysosomal enzymes and proteases</p> Signup and view all the answers

    What is the primary basis of Graves disease?

    <p>Antibody-mediated stimulation of cell function</p> Signup and view all the answers

    Which type of hypersensitivity mainly produces tissue damage by eliciting inflammation at the sites of antigen-antibody complex deposition?

    <p>Type III hypersensitivity</p> Signup and view all the answers

    In which type of reaction are antibodies directed against cell surface receptors, impairing or dysregulating function without causing cell injury or inflammation?

    <p>Cellular dysfunction</p> Signup and view all the answers

    Which leukocytes are activated by engagement of their C3b and Fc receptors during inflammation?

    <p>Granulocytes and monocytes</p> Signup and view all the answers

    What is the role of anaphylatoxins C3a and C5a in antibody-mediated inflammation?

    <p>Vascular permeability increase</p> Signup and view all the answers

    Which cellular process results from activation of leukocytes' C3b and Fc receptors during inflammation?

    <p>Chemotaxis of granulocytes and monocytes</p> Signup and view all the answers

    What enzyme product contributes to the digestion of basement membrane, collagen, elastin, and cartilage by leukocytes during inflammation?

    <p>Collagenase</p> Signup and view all the answers

    What is a defining characteristic of immune complex-mediated diseases?

    <p>Systemic nature with a tendency to involve the kidney, joints, and small blood vessels</p> Signup and view all the answers

    What is one of the common sites for preferential immune complex deposition in immune complex-mediated diseases?

    <p>Joints</p> Signup and view all the answers

    Serum sickness is a prototype of which type of immune complex disease?

    <p>Systemic immune complex disease</p> Signup and view all the answers

    Which phase of the pathogenesis of systemic immune complex disease involves the formation of immune complexes?

    <p>Phase 1</p> Signup and view all the answers

    What is the primary reason serum sickness is now infrequent in modern times?

    <p>Decreased use of immunized horse serum</p> Signup and view all the answers

    Why is serum sickness used as an informative model for systemic immune complex disorders?

    <p>As it provides insights into various phases of pathogenesis</p> Signup and view all the answers

    Which organ is often preferentially involved in systemic immune complex diseases such as glomerulonephritis?

    <p>Kidney</p> Signup and view all the answers

    What is a common characteristic of immune complexes that tend to lead to tissue deposition and disease?

    <p>Medium size and formed under conditions of slight antigen excess</p> Signup and view all the answers

    In which organs does immune complex disease often affect due to the concentration and deposition of immune complexes?

    <p>Glomeruli and joints</p> Signup and view all the answers

    What happens approximately one week after the introduction of a protein antigen?

    <p>Secretion of antibodies into the blood</p> Signup and view all the answers

    Which phase involves the formation of circulating antigen-antibody complexes that are later deposited in vessels?

    <p>Deposition phase</p> Signup and view all the answers

    Which factor plays a major role in determining whether immune complex formation leads to tissue deposition and disease?

    <p>Local vascular alterations</p> Signup and view all the answers

    Where do immune complexes tend to become concentrated due to high pressure filtration of blood, leading to their deposition?

    <p>Kidneys and joints</p> Signup and view all the answers

    What influences the pathogenicity of immune complexes in terms of size and conditions of formation?

    <p>Formation under slight antigen excess conditions</p> Signup and view all the answers

    What is the primary cause of tissue injury in the Arthus reaction?

    <p>Fibrinoid necrosis caused by immune complex precipitation</p> Signup and view all the answers

    What is the main difference between acute and chronic serum sickness?

    <p>Number of exposures to antigen</p> Signup and view all the answers

    Which type of hypersensitivity involves chronic and destructive inflammation mainly mediated by T cells?

    <p>Type IV</p> Signup and view all the answers

    What is the primary mechanism through which antibodies and immune complexes cause tissue injury?

    <p>Activation of leukocytes' Fc receptors</p> Signup and view all the answers

    How does the Arthus reaction differ from delayed-type hypersensitivity (DTH) in terms of tissue injury?

    <p>Dominance of neutrophils in tissue destruction</p> Signup and view all the answers

    Which type of hypersensitivity involves antibodies binding to cell surface receptors, causing functional derangements without cell injury?

    <p>Type II</p> Signup and view all the answers

    What differentiates the immune complex deposition in membranous glomerulonephritis from that in vasculitides?

    <p>Morphologic changes in tissues</p> Signup and view all the answers

    What is the primary role of antibodies in targeting opsonized cells for phagocytosis?

    <p>Coating cells with IgG and complement proteins</p> Signup and view all the answers

    What is the main outcome of antigen diffusing into the vascular wall during the Arthus reaction?

    <p>Formation of large immune complexes</p> Signup and view all the answers

    What happens when CD4+ T cells recognize antigens displayed by dendritic cells (DCs)?

    <p>Differentiation into Thi or Th17 cells driven by APC-produced cytokines</p> Signup and view all the answers

    What is the main morphologic manifestation of immune complex injury discussed in the text?

    <p>Fibrinoid necrosis</p> Signup and view all the answers

    Which clinical feature is NOT commonly associated with the acute inflammatory reaction initiated by immune complexes in tissues?

    <p>Cough</p> Signup and view all the answers

    What is the significance of detecting complement proteins at the site of tissue injury during immune complex-mediated inflammation?

    <p>It supports the role of complement in pathogenesis</p> Signup and view all the answers

    Which observation supports the idea that serum C3 levels can be used to monitor disease activity in certain cases?

    <p>Consumption of complement leading to decreased serum C3 levels</p> Signup and view all the answers

    What is the main appearance of granular lumpy deposits of immunoglobulin and complement in the kidney when viewed under immuno-fluorescence microscopy?

    <p>Electron-dense deposits</p> Signup and view all the answers

    Which cell type is primarily responsible for intense neutrophilic infiltration in fibrinoid necrosis associated with immune complex injury?

    <p>Neutrophils</p> Signup and view all the answers

    What does the term 'acute vasculitis' refer to in the context of immune complex injury?

    <p>Inflammation of blood vessels</p> Signup and view all the answers

    What is the main role of IFN-y-activated macrophages in the context of a delayed-type hypersensitivity reaction?

    <p>Express more class II MHC molecules for antigen presentation</p> Signup and view all the answers

    What is the primary function of Th1 cells upon repeat exposure to an antigen?

    <p>Produce IFN-y to promote delayed-type hypersensitivity</p> Signup and view all the answers

    How do IFN-y-activated macrophages contribute to eliminating offending antigens?

    <p>Enhance phagocytosis and antigen presentation</p> Signup and view all the answers

    Which cytokines are secreted by IFN-y-activated macrophages to promote inflammation?

    <p>TNF and IL-1</p> Signup and view all the answers

    What is the consequence of sustained activation of macrophages during a delayed-type hypersensitivity reaction?

    <p>Continued inflammation and tissue damage</p> Signup and view all the answers

    Which cell type is responsible for the secretion of IL-17 and IL-22 in an inflammatory reaction?

    <p>Th17 cells</p> Signup and view all the answers

    What is the main role of chemokines secreted by activated Th17 cells?

    <p>Recruiting neutrophils and monocytes</p> Signup and view all the answers

    In a delayed-type hypersensitivity (DTH) reaction, what type of cells mainly accumulate around venules?

    <p>CD4+ T cells and macrophages</p> Signup and view all the answers

    What is the morphological feature that characterizes delayed-type hypersensitivity (DTH) reactions?

    <p>Perivascular cuffing</p> Signup and view all the answers

    With persistent antigens like tubercle bacilli, what type of cells dominate the infiltrate over a few weeks?

    <p>Macrophages</p> Signup and view all the answers

    In fully developed lesions of delayed-type hypersensitivity reactions, what morphologic transformation do macrophages often undergo?

    <p>Epithelioid cell transformation</p> Signup and view all the answers

    Which cytokines secreted by activated Th17 cells play a role in recruiting neutrophils to inflammation sites?

    <p>IL-17 and IL-22</p> Signup and view all the answers

    What grossly visible small nodules are formed when aggregates of epithelioid cells are surrounded by lymphocytes?

    <p>Granulomas</p> Signup and view all the answers

    What is the main characteristic that distinguishes a tuberculin reaction in a sensitized individual within 8 to 12 hours?

    <p>Reddening and induration of the site appear.</p> Signup and view all the answers

    Which type of hypersensitivity reaction can be clinically observed as a tuberculin reaction?

    <p>Delayed-type hypersensitivity (DTH)</p> Signup and view all the answers

    What is the main difference between granulomatous inflammation associated with helminthic infections and that induced by indigestible foreign bodies?

    <p>The presence of eosinophils in the former and Th1-cell activation in the latter.</p> Signup and view all the answers

    What is the characteristic feature of contact dermatitis resulting from delayed hypersensitivity reactions?

    <p>Itchy, vesicular (blistering) dermatitis.</p> Signup and view all the answers

    What is the primary mechanism through which tissue injury occurs in rheumatoid arthritis and multiple sclerosis?

    <p>CD8+ T cell-mediated inflammation.</p> Signup and view all the answers

    What is the role of CD8+ CTLs in T cell-mediated reactions?

    <p>Killing antigen-expressing target cells.</p> Signup and view all the answers

    What is the consequence of CTLs directed against cell surface histocompatibility antigens during graft rejection?

    <p>Contributing to graft rejection.</p> Signup and view all the answers

    Which type of immune response involves CD8+ CTLs killing antigen-expressing target cells?

    <p><strong>Type IV hypersensitivity</strong></p> Signup and view all the answers

    Virally infected cells present viral peptides through which type of molecules to be recognized by CD8+ T lymphocytes?

    <p><strong>Class I MHC molecules</strong></p> Signup and view all the answers

    Tumor antigens are presented on the surface of tumor cells, primarily for which purpose?

    <p><strong>Initiating host response to transformed cells</strong></p> Signup and view all the answers

    CD8+ T lymphocytes have a crucial role in which of the following processes?

    <p><strong>Killing antigen-expressing target cells</strong></p> Signup and view all the answers

    Granulomatous reactions rich in eosinophils are typically associated with which type of immune responses?

    <p><strong>Th2 responses</strong></p> Signup and view all the answers

    What is the primary significance of the presence of autoantibodies in the serum of some individuals?

    <p>May have a physiologic role</p> Signup and view all the answers

    How is pathologic autoimmunity typically defined?

    <p>Absence of a well-defined cause of the disease</p> Signup and view all the answers

    In which type of disorder are chronic inflammation and immune response sometimes directed against normally harmless microbes?

    <p>Immune-mediated inflammatory disease</p> Signup and view all the answers

    Which autoimmune disease involves autoreactive T cells and antibodies specific for ß cells of the pancreatic islets?

    <p>Type 1 diabetes</p> Signup and view all the answers

    What distinguishes organ-specific autoimmune diseases from systemic autoimmune diseases?

    <p>The number of involved tissues</p> Signup and view all the answers

    Which autoimmune disease is characterized by antibodies directed against DNA, platelets, and protein-phospholipid complexes?

    <p>SLE</p> Signup and view all the answers

    What is the underlying cause of autoimmunity?

    <p>Loss of self-tolerance</p> Signup and view all the answers

    Which disease sits in the middle of the spectrum between organ-specific and systemic autoimmune diseases?

    <p>'Goodpasture syndrome'</p> Signup and view all the answers

    'Immune-mediated inflammatory diseases' can be classified as autoimmune if the immune response is directed against what?

    <p>'Self antigens'</p> Signup and view all the answers

    What is the primary function of perforin in the I cell-mediated killing of targets?

    <p>Facilitates the release of granzymes from the complex</p> Signup and view all the answers

    Which molecule, expressed by activated CTLs, is homologous to TNF and triggers apoptosis in target cells by binding to the Fas receptor?

    <p>Fas ligand</p> Signup and view all the answers

    What triggers the classical T cell-mediated inflammatory reaction known as DTH?

    <p>Secretion of cytokines</p> Signup and view all the answers

    Which type of cells produce cytokines, notably IFN-γ, following exposure to certain agents and viral infections?

    <p>CD8+ T cells</p> Signup and view all the answers

    Which molecule primarily activates macrophages to produce substances causing tissue damage and promoting fibrosis in CD4+ T cell-mediated hypersensitivity reactions?

    <p>IFN-γ</p> Signup and view all the answers

    In I cell-mediated killing, what is the main function of granzymes released into the target cell cytoplasm?

    <p>Facilitate apoptosis by activating caspases</p> Signup and view all the answers

    Which type of hypersensitivity reaction involves activated CD4+ T cells differentiating into Th1 and Th17 effector cells?

    <p>Type IV</p> Signup and view all the answers

    What is the main role of activated CTLs in I cell-mediated killing?

    <p>Trigger apoptosis in target cells</p> Signup and view all the answers

    Which subset of CD4+ T cells secrete IFN-γ to activate macrophages in hypersensitivity reactions?

    <p>Th1</p> Signup and view all the answers

    What is a characteristic feature of DTH mediated by Th17 effector cells?

    <p>Recruitment of eosinophils to immune response sites</p> Signup and view all the answers

    What is the primary function of central tolerance?

    <p>To eliminate immature self-reactive T and B cells</p> Signup and view all the answers

    What happens to immature T cells that express TCRs specific for self antigens in the thymus?

    <p>They are killed by apoptosis</p> Signup and view all the answers

    What is the purpose of self-tolerance in the immune system?

    <p>To prevent autoimmune diseases</p> Signup and view all the answers

    What is the result of random somatic antigen receptor gene rearrangements in developing lymphocytes?

    <p>The generation of diverse antigen receptors</p> Signup and view all the answers

    What is the difference between central tolerance and peripheral tolerance?

    <p>Central tolerance occurs during lymphocyte maturation, while peripheral tolerance occurs in peripheral tissues</p> Signup and view all the answers

    What is the consequence of a failure in central tolerance?

    <p>The development of autoimmune diseases</p> Signup and view all the answers

    What is the estimated proportion of B cells in the body that may have undergone receptor editing during their maturation?

    <p>One-fourth to one-half</p> Signup and view all the answers

    What happens to self-reactive lymphocytes that escape central tolerance?

    <p>They are removed by peripheral tolerance mechanisms</p> Signup and view all the answers

    What is the outcome if receptor editing does not occur?

    <p>Self-reactive lymphocytes undergo apoptosis</p> Signup and view all the answers

    What is the purpose of central tolerance?

    <p>To remove self-reactive lymphocytes from the mature pool</p> Signup and view all the answers

    What is the result of imperfect central tolerance?

    <p>Some self-reactive lymphocytes escape into the periphery</p> Signup and view all the answers

    What is the primary function of AIRE in the thymus?

    <p>To stimulate the expression of some peripheral tissue-restricted self antigens in the thymus</p> Signup and view all the answers

    What happens to developing B cells that strongly recognize self antigens in the bone marrow?

    <p>They reactivate the machinery of antigen receptor gene rearrangement and begin to express new antigen receptors</p> Signup and view all the answers

    What is the outcome of rare patients with germline loss-of-function mutations in the AIRE gene?

    <p>Develop autoimmune polyendocrine syndrome</p> Signup and view all the answers

    What determines the choice between deletion and development of regulatory T cells in the thymus?

    <p>The affinity of the antigen receptor on immature T cells for antigens present in the thymus</p> Signup and view all the answers

    What is the role of thymic antigen-presenting cells in relation to self antigens?

    <p>To process and present self antigens in association with self MHC molecules to potentially self-reactive T cells</p> Signup and view all the answers

    What is the fate of immature T cells that recognize self antigens in the thymus?

    <p>They are deleted through apoptosis</p> Signup and view all the answers

    What is the primary mechanism by which regulatory T cells suppress immune responses?

    <p>Secretion of immunosuppressive cytokines such as IL-10 and TGF-B</p> Signup and view all the answers

    What is the result of a mutation in the gene encoding IL-2 or the IL-2 receptor alpha or beta chain?

    <p>A rare multiorgan autoimmune disease</p> Signup and view all the answers

    What is the phenotype of T cells that recognize self antigens but are rendered functionally unresponsive?

    <p>Anergy</p> Signup and view all the answers

    What is the association between polymorphisms in the promoter of the CD25 gene and autoimmune diseases?

    <p>Regulatory T-cell defect</p> Signup and view all the answers

    What is the name of the autoimmune disease caused by mutation of the gene encoding FOXP3?

    <p>IPEX</p> Signup and view all the answers

    What is the function of regulatory T cells in the immune system?

    <p>To suppress immune responses to self antigens</p> Signup and view all the answers

    What is the mechanism by which T cells that recognize self antigens are eliminated or inactivated?

    <p>Negative selection</p> Signup and view all the answers

    What is the consequence of a defect in regulatory T cells?

    <p>Autoimmune disease</p> Signup and view all the answers

    What is the primary function of regulatory T cells in placental mammals?

    <p>To prevent immune reactions against fetal antigens inherited from the father</p> Signup and view all the answers

    What is the consequence of inherited mutations in CTLA4?

    <p>Systemic inflammatory diseases</p> Signup and view all the answers

    What is the mechanism by which some tumors evade immune attack?

    <p>By using the same pathways of immune regulation as CTLA-4 and PD-1</p> Signup and view all the answers

    What is the role of FOXP3 transcription factor in placental mammals?

    <p>To stably express regulatory T cells</p> Signup and view all the answers

    Which molecule binds to the ligands PD-L1 and PD-L2?

    <p>PD-1</p> Signup and view all the answers

    What is the outcome when mature B cells encounter self-antigen in peripheral tissues?

    <p>They become unable to respond to subsequent antigenic stimulation and may be excluded from lymphoid follicles</p> Signup and view all the answers

    What type of signal is required for T cell activation in addition to antigen recognition?

    <p>Costimulatory signal</p> Signup and view all the answers

    What is the therapeutic application of blocking CTLA-4 and PD-1?

    <p>Cancer treatment</p> Signup and view all the answers

    What is the result of antigen presentation without adequate costimulation?

    <p>T cell anergy</p> Signup and view all the answers

    What is the role of regulatory T cells in preventing immune responses?

    <p>Against self-antigens and commensal microbes</p> Signup and view all the answers

    What is the function of CTLA-4 and PD-1?

    <p>Coinhibition</p> Signup and view all the answers

    Why do resting DCs in normal tissues lead to anergy?

    <p>They do not express costimulatory molecules</p> Signup and view all the answers

    What is the outcome when B cells encounter self-antigen in peripheral tissues in the absence of specific helper T cells?

    <p>They become anergic</p> Signup and view all the answers

    What is the role of CD28 in T cell activation?

    <p>Costimulatory signal</p> Signup and view all the answers

    Which molecule is structurally homologous to CD28 but serves the opposite function?

    <p>CTLA-4</p> Signup and view all the answers

    What is the result of T cell recognition of self antigens in the absence of costimulation?

    <p>T cell anergy</p> Signup and view all the answers

    What is the consequence of depleting FOXP3+ regulatory T cells in mice?

    <p>Fetal loss</p> Signup and view all the answers

    How do T cells that recognize self-antigens die by apoptosis?

    <p>By expressing Bim without Bcl-2 and Bcl-x</p> Signup and view all the answers

    What is the role of Fas ligand in deletion of mature T cells in the periphery?

    <p>Inducing apoptosis by the death receptor pathway</p> Signup and view all the answers

    What is the consequence of T cells recognizing self-antigens in the periphery?

    <p>Induction of apoptosis</p> Signup and view all the answers

    What is the mechanism by which Bim triggers apoptosis?

    <p>Mitochondrial pathway</p> Signup and view all the answers

    What is the role of Bcl-2 and Bcl-x in T cells that recognize self-antigens?

    <p>Preventing apoptosis</p> Signup and view all the answers

    What is the function of Fas in T cells that recognize self-antigens?

    <p>Inducing apoptosis</p> Signup and view all the answers

    What is the significance of deletion of mature T cells in the periphery?

    <p>Prevention of autoimmune responses</p> Signup and view all the answers

    What happens to self-reactive T cells if they engage with self-antigens?

    <p>They undergo Fas-mediated apoptosis</p> Signup and view all the answers

    What is the main role of regulatory T cells?

    <p>To prevent immune reactions against self-antigens</p> Signup and view all the answers

    What is the function of FasL on T cells?

    <p>To eliminate self-reactive B cells</p> Signup and view all the answers

    What is the consequence of mutations in Fas or FasL?

    <p>Autoimmune lymphoproliferative syndrome (ALPS)</p> Signup and view all the answers

    Which transcription factor is required for the development of regulatory T cells?

    <p>FOXP3</p> Signup and view all the answers

    What is the characteristic of CD4+ regulatory T cells?

    <p>High levels of CD25 and FOXP3 expression</p> Signup and view all the answers

    What is the main function of CD25 in regulatory T cells?

    <p>To bind IL-2 for survival and proliferation</p> Signup and view all the answers

    What is the consequence of mutations in FOXP3?

    <p>Autoimmune diseases</p> Signup and view all the answers

    What is the primary mechanism of immune tolerance in the thymus?

    <p>Clonal deletion of self-reactive T cells</p> Signup and view all the answers

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