Immunology: Immune Cells and Responses
65 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which statement best describes the functional interplay between dendritic cells (DCs) and T cells within the periarteriolar lymphoid sheath (PALS) of the spleen?

  • DCs in the PALS directly activate B cells, which then stimulate T cell proliferation through cytokine release.
  • DCs, after encountering antigens, migrate to the PALS to present these antigens to T cells, initiating adaptive immune responses. (correct)
  • The PALS serves as the primary site for T cell differentiation into NK cells, facilitated by the cytokine environment created by resident DCs.
  • T cells within the PALS phagocytose pathogens, which are then presented to DCs for subsequent antigen presentation to B cells.

A researcher is investigating the immune response in the gut-associated lymphoid tissue. Which of the following characteristics is unique to Peyer's patches compared to other secondary lymphoid organs?

  • Antigen uptake directly from the lumen via M cells. (correct)
  • Presence of HEVs allowing lymphocyte entry.
  • Drainage via efferent lymphatic vessels.
  • Housing of DCs, T cells, and B cells in distinct zones.

Following a severe bacterial infection, a patient's blood work reveals a significantly elevated neutrophil count. Considering the characteristics of neutrophils, which of the following is the most likely consequence of this surge in neutrophil activity?

  • Resolution of the infection site, followed by the development of immunological memory.
  • Long-term enhancement of antibody production by plasma cells.
  • Localized tissue damage due to the release of granular enzymes and reactive oxygen species. (correct)
  • Increased risk of allergic reactions due to histamine release.

In the context of innate immune responses against viral infections, how do Natural Killer (NK) cells differentiate between healthy cells and infected cells, enabling them to selectively target and destroy the latter?

<p>NK cells utilize Fc receptors to bind antibodies coating virally infected cells, triggering antibody-dependent cell-mediated cytotoxicity (ADCC). (D)</p> Signup and view all the answers

A researcher is studying the role of macrophages in maintaining homeostasis within the spleen. Which specific function of splenic macrophages is most critical for preventing systemic complications associated with chronic infections and autoimmune disorders?

<p>Removing immune complexes from the circulation to prevent their deposition in tissues. (A)</p> Signup and view all the answers

Which of the following scenarios would most likely result in a thymocyte undergoing apoptosis during T cell development in the thymus?

<p>A thymocyte with a TCR that displays excessively strong reactivity to self-peptide:self-MHC complexes. (B)</p> Signup and view all the answers

AIRE's (autoimmune regulator) primary role in T cell development is to:

<p>Ensure that medullary stromal cells express a wide array of tissue-specific proteins, facilitating negative selection. (A)</p> Signup and view all the answers

A researcher identifies a genetic defect that prevents thymocytes from upregulating both CD4 and CD8. At which stage of T cell development would this defect have the most immediate impact?

<p>Rearrangement of the TCR alpha chain in double-positive thymocytes. (A)</p> Signup and view all the answers

During T cell development, a thymocyte is positively selected. Which of the following is the most direct consequence of this positive selection?

<p>The thymocyte receives survival signals and proceeds to differentiate into either a CD4+ or CD8+ single-positive T cell. (C)</p> Signup and view all the answers

If a developing thymocyte fails to express a T cell receptor (TCR) with sufficient binding strength to self-peptide:self-MHC complexes, what is the most likely outcome?

<p>The thymocyte will die by neglect due to a lack of survival signals. (B)</p> Signup and view all the answers

Which scenario would most likely result from a defective TH1 response?

<p>Systemic spread of a disease caused by an intracellular pathogen, potentially leading to a fatal outcome. (B)</p> Signup and view all the answers

What is the primary mechanism by which TH2 cells help to eliminate helminth infections?

<p>Coordinating a type 2 immune response to expel helminths through mechanisms like increased mucus production and smooth muscle contraction. (C)</p> Signup and view all the answers

Which of the following best describes how TH1-activated macrophages combat intracellular pathogens?

<p>Enhancing antimicrobial effectiveness through ROS production, secretion of TNFα &amp; IL-12, and upregulation of MHC &amp; costimulatory molecules. (C)</p> Signup and view all the answers

Why are anti-histamines effective in alleviating allergy symptoms?

<p>They block histamine receptors, preventing histamine from exerting its effects on tissues. (D)</p> Signup and view all the answers

What is the role of IL-17 secreted by TH17 cells in coordinating a type 3 immune response?

<p>It leads to the recruitment of neutrophils to the site of infection. (C)</p> Signup and view all the answers

How do memory T cells differ from naive T cells in their trafficking patterns?

<p>Memory T cells express trafficking molecules for extravasation at sites of inflammation/infection, while naive T cells home to SLOs. (D)</p> Signup and view all the answers

What is the significance of IL-7 and IL-15 in the context of immunologic memory?

<p>They are survival factors that help maintain the memory T cell pool. (C)</p> Signup and view all the answers

How do effector T cells adapt to different immunological challenges, particularly in type 3 responses?

<p>By demonstrating plasticity and cooperativity, transitioning into different cytokine production phenotypes as needed. (C)</p> Signup and view all the answers

In the context of lymphocyte trafficking, what determines where effector T cells home after activation?

<p>The adhesion molecules and chemokine receptors expressed on effector T cells, which match the vasculature at the site of inflammation/infection. (D)</p> Signup and view all the answers

What is the primary advantage of immunologic memory compared to the initial adaptive immune response?

<p>Memory responses are faster, of higher affinity, and result in a greater amount of antibodies. (B)</p> Signup and view all the answers

Why is the adaptive immune system considered advantageous compared to the innate immune system, despite its slower response time?

<p>It provides long-lasting immunity through immunological memory. (A)</p> Signup and view all the answers

How do dendritic cells facilitate the adaptive immune response?

<p>By presenting antigens to T cells, initiating clonal selection and expansion. (A)</p> Signup and view all the answers

If a patient has a deficiency in MHC class I molecules, which immune cells would be most directly affected in their ability to function?

<p>CD8+ T cells. (B)</p> Signup and view all the answers

How does the structure of an antibody contribute to its function in the adaptive immune response?

<p>The variable region binds to specific antigens, while the constant region mediates effector functions. (B)</p> Signup and view all the answers

What is the significance of lymphocyte recirculation between blood and lymph nodes in adaptive immunity?

<p>It increases the likelihood of lymphocytes encountering their cognate antigen presented by antigen-presenting cells. (B)</p> Signup and view all the answers

How does the recognition of antigens by T cell receptors (TCRs) differ fundamentally from that of antibodies?

<p>TCRs only recognize peptide fragments of antigens presented on MHC molecules, unlike antibodies that bind to native antigens. (C)</p> Signup and view all the answers

In the context of adaptive immunity, what is the role of the high endothelial venules (HEV) found in the paracortical area of lymph nodes?

<p>They provide entry portals for lymphocytes circulating from the blood into the lymph node. (C)</p> Signup and view all the answers

Considering the different categories of pathogens, why is it crucial for the immune system to have diverse mechanisms for defense?

<p>Different pathogens vary in size, location, and mechanisms of infection, requiring specialized immune strategies. (A)</p> Signup and view all the answers

How does vaccination contribute to the development of adaptive immunity against specific pathogens?

<p>Vaccination induces immunological memory by exposing the immune system to inactivated or attenuated pathogens. (A)</p> Signup and view all the answers

What is the functional implication of the location of B cell follicles in the outermost cortex and T cell zones in the paracortex of a lymph node?

<p>It facilitates the interaction between B cells presenting antigens and activated T cells. (B)</p> Signup and view all the answers

How do antibodies neutralize pathogens to prevent infection?

<p>By blocking the pathogen's ability to bind to host cell receptors. (D)</p> Signup and view all the answers

What role do cytokines and chemokines play in the innate immune response following the detection of PAMPs?

<p>They recruit and activate other leukocytes, amplifying the immune response. (C)</p> Signup and view all the answers

How does the architecture of the inner medulla of a lymph node support the adaptive immune response?

<p>It houses macrophages and antibody-secreting plasma cells, facilitating pathogen clearance and humoral immunity. (A)</p> Signup and view all the answers

What is the primary function of pattern recognition receptors (PRRs) in the innate immune system?

<p>To distinguish between self and nonself by recognizing pathogen-associated molecular patterns (PAMPs). (C)</p> Signup and view all the answers

How would a deficiency in common myeloid progenitors impact the immune system's ability to respond to pathogens?

<p>It would mainly compromise the innate immune response by reducing the numbers of neutrophils, macrophages, and dendritic cells. (A)</p> Signup and view all the answers

How does the co-receptor CD4 or CD8 enhance T cell receptor (TCR) signaling?

<p>By stabilizing the TCR-MHC complex and enabling Lck-mediated phosphorylation of ITAMs. (A)</p> Signup and view all the answers

Which of the following mechanisms is NOT directly involved in turning off or downregulating signaling pathways initiated by receptor tyrosine kinases?

<p>Phosphorylation of signaling proteins, leading to their activation and continued signal propagation. (D)</p> Signup and view all the answers

What is the primary role of scaffold proteins in signal transduction pathways?

<p>To physically bring together multiple signaling proteins, enhancing the efficiency and specificity of signal transduction. (D)</p> Signup and view all the answers

How does Cyclosporin exert its immunosuppressive effects at the molecular level?

<p>By forming a complex with immunophilin to inhibit calcineurin, preventing NFAT activation and IL-2 production. (A)</p> Signup and view all the answers

Which of the following processes is most directly affected by inhibiting the function of phospholipase C-γ (PLC-γ) in T cells?

<p>The activation of the transcription factors NFAT, NFκB, and AP1, which are required for interleukin-2 expression. (A)</p> Signup and view all the answers

A researcher discovers a novel protein that binds specifically to phosphorylated ITIM domains. What is the most likely function of this protein?

<p>Recruiting phosphatases to dampen immune cell activation. (D)</p> Signup and view all the answers

How does the pre-B cell receptor (pre-BCR) signal to enforce allelic exclusion and prevent the expression of multiple BCRs on a single B cell?

<p>By inhibiting further heavy-chain locus rearrangement, ensuring that only one heavy-chain allele is productively rearranged. (B)</p> Signup and view all the answers

A developing B cell in the bone marrow strongly binds to a self-antigen. Which of the following outcomes is LEAST likely to occur as a result of this interaction?

<p>The B cell receives survival signals and becomes activated, migrating to the periphery to mount an autoimmune response. (A)</p> Signup and view all the answers

Mature T cells require a co-stimulatory signal in addition to antigen presentation via MHC to become fully activated. Which of the following scenarios would most likely lead to T cell anergy rather than activation?

<p>A T cell encounters its cognate antigen on a cell that does not express B7 co-stimulatory molecules. (B)</p> Signup and view all the answers

What distinguishes the signaling pathways of the B cell receptor (BCR) from those of the T cell receptor (TCR)?

<p>TCR signaling relies on ZAP-70, whereas BCR signaling uses Syk. (C)</p> Signup and view all the answers

How does CTLA-4 function as a checkpoint inhibitor in T cell activation?

<p>By outcompeting CD28 for binding to B7 molecules on antigen-presenting cells, thereby inhibiting co-stimulatory signaling. (A)</p> Signup and view all the answers

Rapamycin, an mTOR inhibitor, is used to prevent transplant rejection. Which of the following cellular processes is most directly inhibited by rapamycin?

<p>T cell proliferation and cell growth. (B)</p> Signup and view all the answers

Which step in T cell development is most affected by DiGeorge's syndrome, a condition resulting from the failure of the thymus to develop properly?

<p>Positive and negative selection of T cells based on their TCR affinity for MHC molecules. (D)</p> Signup and view all the answers

What role do stromal cells play in B cell development within the bone marrow?

<p>Providing adhesion molecules, growth factors, and survival signals necessary for B cell maturation. (B)</p> Signup and view all the answers

Which of the following events within the immunological synapse enables targeted cytokine release and effective signaling between T cells and antigen-presenting cells?

<p>The clustering of peptide-MHC/TCR complexes and co-stimulatory molecules in the cSMAC. (A)</p> Signup and view all the answers

Which of the following mechanisms is LEAST likely to contribute to tissue damage during an intracellular bacterial infection?

<p>Antibody-mediated opsonization, enhancing phagocytosis without eliciting extensive inflammation. (D)</p> Signup and view all the answers

How does the structure of MBL (mannose-binding lectin) contribute to its function in the lectin pathway of complement activation?

<p>The N-terminal collagen-like domain facilitates the formation of trimers, enhancing the binding avidity to mannose or fructose residues on microbial surfaces. (B)</p> Signup and view all the answers

In the context of the alternative pathway of complement activation, what prevents widespread complement activation on host cell surfaces?

<p>Factor H and Factor I work together to cleave and inactivate C3b deposited on host cells, preventing the formation of the C3 convertase. (D)</p> Signup and view all the answers

Why is the disruption of the intestinal barrier function a critical factor in the pathogenesis of Crohn's disease?

<p>It allows increased transcytosis of commensal bacteria antigens, leading to an overactive T cell response and granulomatous inflammation. (B)</p> Signup and view all the answers

How do epithelial cells in the lungs contribute to innate immunity, and what distinguishes their function from that of goblet cells?

<p>Type II pneumocytes produce antimicrobial defensins, whereas goblet cells secrete mucus to trap pathogens. (D)</p> Signup and view all the answers

Which of the following is NOT a recognized outcome following C3 cleavage during complement activation?

<p>Direct lysis of microbes via the insertion of C3a into the microbial membrane. (D)</p> Signup and view all the answers

What is the significance of the leucine-rich repeats (LRR) found in the extracellular region of Toll-like receptors (TLRs)?

<p>They are responsible for ligand binding, enabling TLRs to recognize specific PAMPs. (B)</p> Signup and view all the answers

How does Staphylococcus aureus evade the complement system, and what is the practical implication of this mechanism?

<p>By producing protein A, which binds to the Fc portion of antibodies, preventing complement activation and opsonization; this is also exploited for affinity chromatography. (D)</p> Signup and view all the answers

What distinguishes the activation mechanism of NLRP3 from that of NOD2 in cytosolic PRRs?

<p>NLRP3 forms an inflammasome in response to diverse cellular stressors, while NOD2 dimerizes to activate NF-κB in response to microbial products. (C)</p> Signup and view all the answers

How do RIG-I-like receptors (RLRs) discriminate between self and non-self RNA in the cytosol, and what is the outcome of their activation?

<p>RLRs target RNA with specific capping structures unique to viral RNA, leading to the activation of IRF3 and NFκB. (C)</p> Signup and view all the answers

Considering the role of cGAS/STING in innate immunity, what would be the MOST likely consequence of a loss-of-function mutation in the STING protein?

<p>Impaired production of type I interferons in response to cytosolic DNA. (C)</p> Signup and view all the answers

How do chemokines contribute to the extravasation of leukocytes during inflammation, and what is their primary mechanism of action?

<p>They activate integrins on leukocytes, promoting tight binding to adhesion molecules on endothelial cells. (A)</p> Signup and view all the answers

Explain the significance of co-stimulatory molecules like CD80 and CD86 in the context of adaptive immunity, and what role do adjuvants play in this process?

<p>CD80 and CD86 are required for fully activating naïve T cells by antigen-presenting DCs, and adjuvants enhance their expression. (A)</p> Signup and view all the answers

How does TNF-α contribute to both local containment of an infection and systemic septic shock, and what factors determine which outcome predominates?

<p>TNF-α at local concentrations promotes leukocyte recruitment and containment, while high systemic TNF-α leads to vasodilation, vascular permeability, and septic shock. (A)</p> Signup and view all the answers

In X-linked Severe Combined Immunodeficiency (X-SCID) caused by mutations in the common γ chain receptor, which of the following immune deficiencies would be LEAST expected?

<p>Inability to produce type I interferons in response to viral infections. (B)</p> Signup and view all the answers

Flashcards

Efferent lymphatics

Exit routes for lymphocytes from lymph nodes.

Spleen red pulp

Part of the spleen involved in red blood cell destruction and disposal.

Dendritic cells

Immune cells that phagocytose and activate T lymphocytes after maturation.

NK cells

Innate immune cells lacking specific receptors, destroy infected cells and tumors.

Signup and view all the flashcards

Granulocytes

Short-lived immune cells like neutrophils that rapidly respond to infections.

Signup and view all the flashcards

Double-negative thymocytes

Thymocytes that lack both CD4 and CD8 markers during early thymic development.

Signup and view all the flashcards

Double-positive cells

Thymocytes that express both CD4 and CD8 during development, enabling them to interact with MHC molecules.

Signup and view all the flashcards

Positive selection

The process where thymocytes that can interact with self MHC molecules receive survival signals, leading to their further development.

Signup and view all the flashcards

Negative selection

The elimination of thymocytes that react strongly with self antigens, preventing autoimmunity.

Signup and view all the flashcards

AIRE function

Autoimmune regulator that promotes transcription of tissue-specific proteins in thymic medullary stromal cells for negative selection.

Signup and view all the flashcards

Edward Jenner

Pioneer of vaccination, using smallpox inoculation.

Signup and view all the flashcards

Intracellular Bacteria/Protozoa

Microorganisms cleared by macrophages with T cell assistance.

Signup and view all the flashcards

Endotoxins

Components of microbes triggering immune responses, e.g. LPS from Gram-negative bacteria.

Signup and view all the flashcards

Leukocytes

White blood cells that protect against infections.

Signup and view all the flashcards

Immune System Function

Mainly protects the body from pathogens.

Signup and view all the flashcards

Exotoxins

Secreted toxins by microorganisms that affect host cells.

Signup and view all the flashcards

Pathogen Categories

Includes viruses, bacteria, fungi, and parasites.

Signup and view all the flashcards

Defensins

Antimicrobial peptides that disrupt microbial membranes.

Signup and view all the flashcards

Lysozyme

Enzyme that digests bacterial cell walls, more effective on Gram-positive bacteria.

Signup and view all the flashcards

Innate Immune System

First line of defense, responds quickly to pathogens.

Signup and view all the flashcards

Complement System

Group of proteins that detect and destroy microorganisms via a cascade reaction.

Signup and view all the flashcards

Adaptive Immune System

Tailored response to specific pathogens, takes time to develop.

Signup and view all the flashcards

Phagocytosis

Process by which phagocytes ingest and destroy pathogens.

Signup and view all the flashcards

Antigen-Presenting Cells

Cells that display antigens to T cells, like dendritic cells.

Signup and view all the flashcards

Anaphylatoxins

C3a and C5a that cause inflammation and recruit leukocytes.

Signup and view all the flashcards

Toll-like Receptors (TLR)

Receptors that recognize pathogens and activate immune responses.

Signup and view all the flashcards

Antibodies

Proteins that bind to specific antigens to neutralize them.

Signup and view all the flashcards

NOD-like Receptors (NLR)

Cytosolic receptors that detect microbial products and activate inflammation pathways.

Signup and view all the flashcards

MHC Molecules

Proteins that present antigen fragments on cell surfaces.

Signup and view all the flashcards

Regulatory Proteins

Proteins that prevent unwanted complement activation in host cells.

Signup and view all the flashcards

Cytokines

Small proteins that mediate communication between immune cells.

Signup and view all the flashcards

Antibody Titer

The concentration of antibodies in blood over time.

Signup and view all the flashcards

Neutrophils

Short-lived immune cells that are first responders to inflammation sites.

Signup and view all the flashcards

Clonal Selection

Process where T cells are activated and proliferate upon antigen recognition.

Signup and view all the flashcards

Epitope

The specific part of an antigen recognized by an antibody.

Signup and view all the flashcards

Macrophages

Large phagocytic cells that produce cytokines to regulate immune response.

Signup and view all the flashcards

Morbus Crohn

Inflammatory disease of intestine linked to T cell responses against gut bacteria.

Signup and view all the flashcards

Kinases

Enzymes that add phosphate groups to proteins, activating them.

Signup and view all the flashcards

Phosphatases

Enzymes that remove phosphate groups from proteins, deactivating them.

Signup and view all the flashcards

Phosphorylation

The process of adding a phosphate group to a protein, affecting its activity.

Signup and view all the flashcards

Dephosphorylation

The removal of a phosphate group, leading to the inactivation of the protein.

Signup and view all the flashcards

Scaffold proteins

Large proteins that organize and localize signaling proteins at the membrane.

Signup and view all the flashcards

Adaptor proteins

Proteins that facilitate the interaction between two different proteins in signaling.

Signup and view all the flashcards

Small G proteins

Molecular switches that relay signals from receptors; activated by GEFs & GTP.

Signup and view all the flashcards

Immune synapse

The contact area between T cells and antigen-presenting cells facilitating communication.

Signup and view all the flashcards

ITAM

Immunoreceptor Tyrosine-based Activation Motif; crucial for TCR and BCR signaling.

Signup and view all the flashcards

ZAP-70

A kinase recruited by phosphorylated ITAMs that amplifies T cell signaling.

Signup and view all the flashcards

CD28

A co-stimulatory receptor on T cells enhancing activation via B7 ligands.

Signup and view all the flashcards

CTLA-4

An inhibitory receptor on T cells that downregulates immune activation.

Signup and view all the flashcards

RAG-1/2 enzymes

Enzymes needed for the rearrangement of B cell receptor genes during development.

Signup and view all the flashcards

IL-2

A cytokine crucial for T cell survival and proliferation.

Signup and view all the flashcards

Rapamycin

A drug that inhibits the mTOR pathway, reducing cell growth and proliferation.

Signup and view all the flashcards

TH1 cells

Effector T-helper cells that target intracellular bacteria and protozoa.

Signup and view all the flashcards

TH2 cells

Effector T-helper cells that combat parasites, particularly helminths.

Signup and view all the flashcards

TH17 cells

Effector T-helper cells that enhance defense against extracellular bacteria and fungi.

Signup and view all the flashcards

TFH cells

Follicular T-helper cells that support B cell activity and antibody production.

Signup and view all the flashcards

Tregs

Regulatory T cells that help suppress immune responses to prevent autoimmunity.

Signup and view all the flashcards

Cytotoxic CD8+ T cells

T cells that directly kill virally infected and tumor cells.

Signup and view all the flashcards

Immunologic memory

The ability of the immune system to remember past infections for faster response.

Signup and view all the flashcards

Memory T cells

Long-lived T cells formed from effector cells that respond quickly upon re-exposure.

Signup and view all the flashcards

Lymphocyte trafficking

Movement of lymphocytes to sites of infection or inflammation.

Signup and view all the flashcards

Chronic TH1 activation

Sustained TH1 cell activity leading to granulomas and persistent infections.

Signup and view all the flashcards

Study Notes

Pharmaceutical Immunology

  • Edward Jenner pioneered vaccination, inoculating individuals with weakened pathogens to induce immunity.
  • Smallpox was eradicated in 1979.
  • Immune systems primarily protect from infection via leukocytes (T cells, B cells, NK cells, eosinophils, basophils, neutrophils, immature dendritic cells, monocytes) and lymphoid organs (bone marrow & thymus; Peyer's patches, spleen, tonsils, appendix, lymph nodes).
  • Bone marrow is the source of blood cells, producing leukocytes, erythrocytes, and platelets.

Levels of Defense

  • Anatomical barriers (skin, oral mucosa, respiratory epithelium, intestines) are the initial lines of defense.
  • Innate immune cells (macrophages, granulocytes, NK cells) and adaptive immunity (B/antibodies, T cells) work towards eliminating pathogens in more complex ways.

Innate Immune System

  • Microbes have pathogen-associated molecular patterns (PAMPs) detected by sensor cells like macrophages, neutrophils, and dendritic cells.
  • This detection triggers inflammatory mediators (cytokines/chemokines), amplifying the response, recruiting other leukocytes, inducing antimicrobial/antiviral factors.
  • Inflammatory inducers include bacterial lipopolysaccharides, ATP and urate crystals.
  • Key receptors of innate immunity include Toll-like receptors (TLRs).

Adaptive Immune System

  • Key link between innate and adaptive immune systems is dendritic cells (DCs),
  • T cells destroy infected cells; B cells secrete antibodies. Antibodies bind to antigens (foreign structures) to inactivate them;
  • Key link between innate & adaptive immunity = T cells recognizing antigens presented by DCs activate B cells for antibody production
  • Lymphocytes recirculate between blood & lymph nodes to increase the chance of antigen encounter.
  • Clonal selection expands lymphocytes responding to a specific antigen.
  • Antibodies are Y-shaped molecules with variable regions for antigen binding and constant regions for effector function

Antibody and TCR structure

  • Antibodies consist of two heavy and two light chains, linked by disulfide bridges
  • Variable regions determine antigen specificity and constant regions for effector functions (neutralization, opsonization).
  • T cell receptors (TCRs) are composed of α and β chains.
  • TCRs recognize antigen in complex with MHC molecules.

MHC molecules

  • Expressed on cells, MHC class I presents self-proteins and viral peptides for cytotoxic T cells (CTL). MHC class II presents foreign peptides to helper T cells.
  • Peptides from pathogens are presented.

Cells of the immune system

  • Macrophages: long-lived phagocytic cells that ingest and destroy bacteria
  • Granulocytes: neutrophils, eosinophils, basophils have short lifespans, take pathogens into cells and kill them
  • Mast cells: release histamine and inflammatory molecules
  • Dendritic cells: phagocytic cells, present antigens to T cells, migrate through lymphoid tissue
  • Natural killer (NK) cells: destroy virus-infected cells, kill infected cells (NK can also kill cancerous cells)

Complement system

  • System of soluble, pattern recognition receptors & effector molecules detects and destroys micro-organisms in blood
  • The classical, alternative and lectin pathways activate components that tag pathogens for elimination by phagocytic cells or that directly destroy cells
  • Complement activation triggers inflammation (C3a and C5a).
  • The complement cascade leads to the membrane attack complex (MAC), which disrupts cell membranes.

The Induced Response of Innate Immunity

  • PRRs (pattern recognition receptors) recognise PAMPs or DAMPs.
  • Microbes are recognised, ingested, and killed by macrophages & resident phagocytic cells.
  • Bactericidal agents kill pathogens.
  • Includes respiratory burst producing reactive oxygen species (ROS).

Molecular mechanisms of the innate immune system

  • PAMPs recognised by preformed pattern recognition receptors (PRRs).
  • Leads to the cascade of activation, triggering inflammation, phagocytosis, and/or lysis

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Pharmaceutical Immunology Summary PDF

Description

Explore the interplay of dendritic and T cells, Peyer's patches, neutrophil activity during infection, and NK cell targeting of infected cells. Learn about the role of macrophages in maintaining homeostasis within the spleen.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser