The Immune System Overview
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What is the primary function of primary lymphoid organs?

  • Site where immune cells mature and stem cells divide. (correct)
  • Store immune cells for later use.
  • Filter microbes from the body.
  • Produce antibodies in response to infections.

    • Which immune cells are produced in the bone marrow?

  • Natural killer cells and memory T-cells.
  • B-cells and immature T-cells. (correct)
  • Immature T-cells and dendritic cells.
  • Macrophages and plasma cells.

    • What role do lymph nodes play in the immune response?

  • Mature B-cells and release them into the bloodstream.
  • Produce antibodies before an infection occurs.
  • Filter microbes and facilitate phagocytosis. (correct)
  • Store old erythrocytes and dead cells.

    • How do secondary lymphoid organs differ from primary lymphoid organs?

    <p>Secondary organs are involved in immune responses, while primary organs are for cell maturation.</p> Signup and view all the answers

    Which of the following statements about the thymus is correct?

    <p>It atrophies after the maturation of immune cells.</p> Signup and view all the answers

    What is the primary role of the immune system?

    <p>To protect the body from pathogens and altered cells</p> Signup and view all the answers

    Which statement correctly describes non-specific/innate immunity?

    <p>Acts as the first-line of defense without recognizing pathogens</p> Signup and view all the answers

    What distinguishes specific/adaptive immunity from non-specific/innate immunity?

    <p>It requires pathogen recognition and improves upon subsequent exposure</p> Signup and view all the answers

    How does the immune system respond to foreign tissues such as transplants?

    <p>By mounting an immune response to reject the foreign tissue</p> Signup and view all the answers

    What are Pathogen-Associated Molecular Patterns (PAMPs)?

    <p>Molecules recognized as harmful by the immune system</p> Signup and view all the answers

    What is the primary function of Toll-Like Receptors (TLRs)?

    <p>To recognize microbial patterns through PAMPs</p> Signup and view all the answers

    Which of the following is NOT a stage of inflammation?

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

    Which process involves phagocytes moving across the capillary wall?

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

    What do neutrophils form during the process of eliminating bacteria?

    <p>Neutrophil Extracellular Traps (NETs)</p> Signup and view all the answers

    What role do chemokines play during the inflammatory response?

    <p>They attract phagocytes to the site of infection.</p> Signup and view all the answers

    What is a consequence of neutrophils dying after killing bacteria?

    <p>They form Neutrophil Extracellular Traps.</p> Signup and view all the answers

    Which of the following is a characteristic of PAMPs?

    <p>They are conserved structures across different microbes.</p> Signup and view all the answers

    What is the primary function of MHC I molecules?

    <p>To express on all nucleated cells</p> Signup and view all the answers

    Which of the following cells are classified as antigen-presenting cells (APCs)?

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

    Which best describes the relationship between T-cell receptors and MHC II proteins?

    <p>T-cell receptors recognize antigens only when bound to MHC II</p> Signup and view all the answers

    What antigen characteristics are crucial for eliciting an immune response?

    <p>Immunogenicity and Reactivity</p> Signup and view all the answers

    What role do macrophages play in the immune system?

    <p>They serve as professional APCs presenting antigens with MHC II</p> Signup and view all the answers

    In which scenario might a natural killer cell become activated?

    <p>When MHC I is absent or altered</p> Signup and view all the answers

    What is the first step in the antigen presentation process by APCs?

    <p>Ingest the antigen</p> Signup and view all the answers

    Which statement best describes the uniqueness of MHC molecules among individuals?

    <p>Only identical twins share the same MHC molecules</p> Signup and view all the answers

    What type of immune cell is primarily responsible for destroying multicellular parasites?

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

    Which cells secrete cytokines to activate other immune cells?

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

    Where are neutrophils produced?

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

    Which of the following immune cells can transform into macrophages?

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

    What is the function of plasma cells?

    <p>To secrete antibodies</p> Signup and view all the answers

    Which type of T cell directly destroys virus-infected cells?

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

    What role do mast cells play in the immune response?

    <p>Secreting histamine and other chemicals</p> Signup and view all the answers

    Which of the following is NOT a component of the second line of defense in innate immunity?

    <p>Antibody production</p> Signup and view all the answers

    Which of the following factors are involved in the process of inflammation?

    <p>All of the above</p> Signup and view all the answers

    Which feature distinguishes specific/adaptive immunity from non-specific/innate immunity?

    <p>Ability to produce antibodies</p> Signup and view all the answers

    Which cells are considered professional antigen-presenting cells (APCs)?

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

    What type of immune response involves the release of chemicals such as histamine?

    <p>Non-specific inflammatory response</p> Signup and view all the answers

    What is a primary function of neutrophils during an immune response?

    <p>Phagocytosis of pathogens</p> Signup and view all the answers

    What role do memory cells play in the immune response?

    <p>They expand the pool of lymphocytes for quicker response to antigens.</p> Signup and view all the answers

    Which of the following best describes clonal expansion in lymphocytes?

    <p>The replication of lymphocytes with specific receptors for an antigen.</p> Signup and view all the answers

    What is the primary outcome of the interaction between antibodies and FC receptors?

    <p>Release of Granzymes and Perforin by NK cells.</p> Signup and view all the answers

    During a secondary immune response, which factor contributes to a more rapid antibody production?

    <p>Higher concentration of specific memory cells available.</p> Signup and view all the answers

    Which component of the antibody is responsible for its specificity to an antigen?

    <p>The FAB region of the antibody.</p> Signup and view all the answers

    What is the role of Natural Killer (NK) Cells in the immune system?

    <p>Identify and destroy virus-infected cells</p> Signup and view all the answers

    During the activation of Helper T Cells, what role do cytokines play?

    <p>They enhance the cellular response of T Cells and B Cells</p> Signup and view all the answers

    What is the main difference between the innate immune system and the adaptive immune system?

    <p>Only adaptive immunity has memory for previously encountered antigens</p> Signup and view all the answers

    Which cells are primarily responsible for the direct attack against infected body cells?

    <p>Cytotoxic T Cells</p> Signup and view all the answers

    How do macrophages assist in the immune response?

    <p>They present antigens and activate T Cells</p> Signup and view all the answers

    What triggers the recruitment of neutrophils during an immune response?

    <p>The Danger signal from macrophages</p> Signup and view all the answers

    What type of T Cell is involved in linking the innate to the adaptive immune system?

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

    Which statement best summarizes the function of plasma cells?

    <p>They produce and secrete antibodies</p> Signup and view all the answers

    What is the role of Recombination Activating Genes (RAGs) in B cell development?

    <p>They are involved in immunoglobulin gene rearrangement.</p> Signup and view all the answers

    Which of the following proteins is specifically important for the rearrangement of DNA during B cell development?

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

    What is produced when the heavy-chain primary RNA transcript undergoes processing?

    <p>Heavy-chain messenger RNA</p> Signup and view all the answers

    What stage comes directly after the formation of the pre-B cell?

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

    What is the purpose of the surrogate light chain in B cell development?

    <p>To stabilize the pre-B cell receptor.</p> Signup and view all the answers

    Which component is responsible for the rearrangement of the D and J gene segments in B cells?

    <p>RAG1</p> Signup and view all the answers

    Which option correctly describes the sequence of B cell maturation from progenitor to functional cell?

    <p>Pro-B cell → Pre-B cell → Mature B cell → Plasma cell</p> Signup and view all the answers

    What chain is formed in a B cell after the successful rearrangement of immunoglobulin genes?

    <p>Heavy chain</p> Signup and view all the answers

    What is the role of Helper T Cells (TH) in the immune response?

    <p>Activate B and Cytotoxic T Cells.</p> Signup and view all the answers

    Which process allows for the variation in the antibodies produced by B cells?

    <p>Class-switching</p> Signup and view all the answers

    What initiates the Membrane Attack Complex (MAC) in the complement cascade?

    <p>Activation of C1 by antigen-antibody complexes</p> Signup and view all the answers

    What type of immunity involves the use of antibodies produced by another organism?

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

    What is one of the primary roles of humoral immunity involving antibodies?

    <p>To guide phagocytes and activate complement systems.</p> Signup and view all the answers

    Memory cells are formed as a result of what process during the adaptive immune response?

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

    Which component of the immune system is primarily responsible for the direct attack on antigen-bearing cells?

    <p>Cytotoxic T Cells</p> Signup and view all the answers

    What is an important function of antigen-presenting cells (APCs) in the immune system?

    <p>Activating T Cells.</p> Signup and view all the answers

    Which region of the B-Cell Receptor is responsible for determining the specificity of the antibody?

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

    What role do RAG1 and RAG2 proteins play in B cell development?

    <p>Mediate V(D)J recombination</p> Signup and view all the answers

    Which process is mediated by Terminal deoxynucleotidyl transferase (TdT) during B cell maturation?

    <p>Adding nucleotides at gene junctions</p> Signup and view all the answers

    Which type of B cell is characterized by the expression of a fully formed B cell receptor?

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

    What component's rearrangement occurs first during B cell receptor development?

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

    What is the primary function of B cells once they have differentiated into plasma cells?

    <p>Antibody secretion</p> Signup and view all the answers

    Which of the following sequences occurs in B cell receptor maturation?

    <p>Heavy chain rearrangement, light chain rearrangement, and expression of B cell receptor</p> Signup and view all the answers

    Which segment influences the diversity of antibody specificity in B cells?

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

    What is the purpose of the heavy-chain primary RNA transcript in B cell maturation?

    <p>To produce a precursor for mature mRNA</p> Signup and view all the answers

    Which stage of B cell development occurs just before the B cell becomes fully immunocompetent?

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

    During which process are gene segments spliced out to enable B cell receptor diversity?

    <p>Gene rearrangement</p> Signup and view all the answers

    Which of the following features is unique to mature B cells compared to their precursors?

    <p>Ability to secrete antibodies</p> Signup and view all the answers

    Which component of B cell receptors is responsible for recognizing and binding to antigens?

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

    What is the primary cause of decreased resistance to infection globally?

    <p>Protein-calorie malnutrition</p> Signup and view all the answers

    What results from the negative selection process in T cell development?

    <p>Destruction of T cells that recognize self-proteins</p> Signup and view all the answers

    Which T cell type is primarily responsible for recognizing endogenous antigens?

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

    Which immune response mechanism involves the displacement of CD28 by CTLA4?

    <p>Checkpoint inhibition</p> Signup and view all the answers

    Which type of hypersensitivity involves symptoms appearing 12-72 hours after exposure?

    <p>Delayed hypersensitivity</p> Signup and view all the answers

    What role do MHC proteins play in organ transplantation?

    <p>Cause tissue rejection</p> Signup and view all the answers

    What condition is characterized by an absence of both B and T cells?

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

    Which of the following statements is true regarding the ABO blood group system?

    <p>Group A has Anti-B antibodies</p> Signup and view all the answers

    What occurs during anaphylaxis related to allergic reactions?

    <p>Activation of mast cells leads to systemic symptoms</p> Signup and view all the answers

    Which factors affect the body's resistance to infections?

    <p>Nutrition and sleep</p> Signup and view all the answers

    What is a common outcome for lymphocytes during the development of tolerance?

    <p>Clonal deletion of self-reactive cells</p> Signup and view all the answers

    What do mast cells release during an allergic reaction?

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

    How does stress influence the immune system?

    <p>Decreases the production of antibodies</p> Signup and view all the answers

    What is the primary mechanism of immune tolerance?

    <p>Clonal deletion of self-reactive lymphocytes</p> Signup and view all the answers

    Study Notes

    The Immune System

    • The immune system encompasses the entire body and its various organs through lymph and blood
    • It protects against pathogens (Bacteria, Viruses, Parasites) and altered body cells (Cancer)
    • It can potentially attack healthy cells by mistake, leading to autoimmune disorders or attacking transplanted tissues
    • The immune system has two main branches: Non-specific (Innate) and Specific (Adaptive)

    Strategies for Protection

    • Non-Specific/Innate immunity:
      • The body's first line of defense
      • Does not require recognition of a specific pathogen
      • Same response each time it encounters a pathogen
    • Specific/Adaptive immunity:
      • Requires recognition of a specific pathogen
      • Faster response with repeated exposure to the same pathogen

    Components of the Immune System - Lymphoid Organs

    • Primary Lymphoid Organs:
      • Locations where stem cells divide and immune cells develop
      • Bone Marrow: Produces blood cells (B cells and immature T cells), matures B cells
      • Thymus: Located above the heart, matures T cells, contains T cells, dendritic cells, epithelial cells, and macrophages
    • Secondary Lymphoid Organs:
      • Sites where most immune responses occur
      • Lymph Nodes: Scattered throughout the body, filter microbes, macrophages phagocytize microbes in lymph
      • Spleen: Largest lymphoid organ, removes microbes and old erythrocytes
      • Lymphoid Nodules: Small aggregations of lymphoid tissue found in different locations
      • Tonsils: Lymphoid tissue in the throat
      • Peyer’s Patches and MALT (Mucosal-Associated Lymphoid Tissues): Found in the intestines
      • Appendix: Small, finger-shaped pouch that extends from the colon

    Immune Cells

    • Leukocytes (white blood cells):
      • Lymphoid Cells:
        • T Cells:
          • Cytotoxic T-Cells (CD8+): Destroy virus-infected cells, cancer cells, and transplanted tissues
          • Helper T-Cells (CD4+): Secrete cytokines to activate B cells, cytotoxic T cells, NK cells, and macrophages
          • Regulatory T-Cells (CD4+): Suppress the immune system to prevent autoimmune reactions
        • B Cells: Produce antibodies
        • NK Cells (Natural Killer Cells): Bind and kill virus-infected cells and cancer cells
      • Myeloid Cells:
        • Macrophage: Phagocytize microbes and debris, present antigens to T cells
        • Dendritic Cells: Phagocytize microbes and present antigens to T cells

    Immune Cells - Myeloid Lineage

    • Eosinophils: Destroy parasites
    • Basophils: Release histamine and other chemicals
    • Mast Cells: Release histamine and other chemicals
    • Neutrophils: Highly mobile phagocytes that are the first responders to an infection
    • Monocytes: Become macrophages and dendritic cells

    Specific Role of Immune Cells

    • Neutrophils: Phagocytize bacteria, release chemicals, and die in the process of killing bacteria
    • Basophils: Release histamine in blood similar to mast cells in tissues
    • Eosinophils: Destroy multicellular parasites, participate in allergic reactions
    • Monocytes: Migrate to tissues and become macrophages
    • Lymphocytes:
      • B cells: Initiate antibody-mediated immune responses by binding antigens to their surface receptors
      • T cells (TH and TC): Recognize specific antigens and activate other immune cells
      • Cytotoxic T Cells (CD8+): Directly kill target cells by binding to antigens on their surface
      • Helper T Cells (CD4+): Secrete cytokines that help activate other immune cells
    • Macrophages: Phagocytize microbes and debris, release toxic chemicals, present antigens to T cells, and contribute to inflammation
    • Dendritic Cells: Phagocytize microbes and present antigens to T cells, also known as "professional APCs"
    • Mast Cells: Release histamine and other chemicals involved in inflammation, found in tissues
    • Plasma Cells: Secrete antibodies

    Major Histocompatibility Complex (MHC)

    • Two classes:
      • MHC I: Found on all nucleated cells, presents internal antigens (antigens from within the cell)
      • MHC II: Found on antigen-presenting cells (macrophages, dendritic cells, B cells), presenting antigens from outside the cell
    • Only identical twins share the same MHC molecules

    Antigen Presenting Cells

    • Present exogenous antigens (antigens taken up from outside the cell) with MHC II molecules. This process involves:
      • Ingesting the antigen
      • Digesting it into peptide fragments
      • Binding peptide fragments to MHC II molecules
      • Inserting these complexes onto the cell surface

    Adaptive Immune Response

    • Antigen Requirements:
      • Reactivity: The ability of an antibody to bind specifically to the antigen that provoked it
      • Immunogenicity: The ability of an antigen to stimulate an immune response and trigger antibody production
    • Antigen-Presenting Cells (APCs):
      • Dendritic cells: Professional antigen-presenting cells
      • Macrophages: Phagocytize microbes and present antigens to Helper T cells
      • B Lymphocytes: Present antigens to Helper T cells

    Host Defenses

    • Non-Specific/Innate Immunity:
      • The body's first line of defense against pathogens
      • No memory of previous encounters with pathogens
      • First Line of Defense: Physical barriers like skin, mucous membranes, and cilia
      • Second Line of Defense: Cellular factors (phagocytes, natural killer cells) and Humoral factors (inflammation, antimicrobial substances, interferons)
    • Specific/Adaptive Immunity:
      • Involves memory of previous encounters with pathogens
      • B cells and T cells are the main players
      • Requires recognition of specific foreign materials
      • Much stronger and more effective than innate immunity

    Inflammation

    • Non-specific response to tissue damage
    • Signs and Symptoms: Redness, heat, pain, swelling
    • Stages:
      • Vasodilation: Widening of blood vessels to increase blood flow
      • Emigration of Phagocytes: Phagocytes move from the bloodstream to the site of inflammation
      • Tissue Repair: Damaged tissue is repaired
    • Trigger: Toll-like receptors (TLRs) on macrophages recognize Pathogen-Associated Molecular Patterns (PAMPS) on microbes, initiating the inflammatory response

    Toll-Like Receptors (TLRs)

    • Transmembrane receptors that are highly conserved in evolution
    • Recognize PAMPs on microbes (e.g., lipopolysaccharides of gram-negative bacteria, peptidoglycans of gram-positive bacteria)
    • Extracellular domain recognizes pathogens
    • Intracellular signaling domain initiates downstream signaling cascades

    The Inflammatory Response

    • Neutrophils are attracted to the site of inflammation by chemokines
    • Adhesion of neutrophils to blood vessel walls (margination)
    • Neutrophils cross blood vessel walls (diapedesis)
    • Neutrophils phagocytize bacteria and release toxic chemicals
    • NETs (Neutrophil Extracellular Traps): Chromatin bound to proteins released by neutrophils

    The Major Histocompatibility Complex (MHC)

    • Presents antigens to T cells
    • MHC I: Found on all nucleated cells
    • MHC II: Found on antigen-presenting cells

    Immunology Lecture 3

    • Immune System Defense: The immune system defends the body against specific microbes and foreign substances through a complex process involving both non-specific (innate) and specific (adaptive) immunity.

    • Innate Immune System: The innate immune system is the body's first line of defense and is characterized by non-specific responses to pathogens.

    • Natural Killer Cells: Natural killer (NK) cells are important in innate immunity. They attack cells that lack MHC Class I expression, which is often seen in tumor cells and virally infected cells. They release granzymes and perforin when activated by the interaction between their antibody and the FC receptor.

    • Phagocytic Cells: Phagocytic cells play a crucial role in eliminating invading pathogens.

      • Fixed-Tissue Macrophages: These cells are resident in tissues, acting as sentinels against microbes and foreign substances. They recognize pathogen-associated molecular patterns (PAMPs) through Toll-like receptors (TLRs) and release signals for neutrophil recruitment.

      • Neutrophils: These cells are also a major part of the innate immune system and are recruited to sites of infection. They undergo margination, emigration, and NET formation to trap and kill invading pathogens.

      • Dendritic Cells: Dendritic cells are professional antigen-presenting cells (APCs) that bridge the innate and adaptive immune systems. They express MHC Class II molecules and present antigens to T cells in lymph nodes, promoting the immune response.

    • Adaptive Immune System: The adaptive immune system provides a specific and targeted defense against pathogens that have bypassed the innate immune system.

    • B and T Lymphocytes: B and T lymphocytes are key players in adaptive immunity. They are responsible for recognizing and responding to specific antigens.

      • Helper T Cells (TH): Helper T cells play a central role in activating both B cells and cytotoxic T cells, coordinating the immune response.

      • B Cells: B cells differentiate into plasma cells, which produce and secrete antibodies. Antibodies contribute to the humoral response, targeting pathogens and activating the complement system.

      • Cytotoxic T Cells (TC): Cytotoxic T cells directly attack infected cells, cancerous cells, or foreign cells. They are part of cell-mediated immunity.

    • Antigen Presentation: Antigen-presenting cells (APCs) process and present antigens to helper T cells (TH). The interaction between the APC and the TH is central to the activation of the adaptive immune response.

    • Helper T Cell Activation: Helper T cell activation requires several steps:

      • Antigen Recognition: The helper T cell (TH) must recognize the specific antigen presented by the APC via MHC Class II molecules.

      • Co-Stimulation: The TH must receive co-stimulatory signals from the APC.

      • Cytokine Production: The APC produces cytokines that further stimulate the TH.

    • Lymphocyte Activation and Differentiation: Activation of helper T cells leads to the production of cytokines, which in turn, activates B cells and cytotoxic T cells. This results in the differentiation of B cells into plasma cells, secreting antibodies, and the activation of cytotoxic T cells to kill infected cells.

    • Memory Cells: Upon activation, lymphocytes generate memory cells, which retain the capability of recognizing and responding more rapidly to the same antigen upon re-exposure. This mechanism ensures a faster and more efficient response during subsequent infections.

    • Antibody Production: Antibodies are produced by plasma cells in response to antigen stimulation. They consist of two regions:

      • FAB Region: This region binds to the specific antigen.

      • FC Region: This region interacts with other immune cells and proteins, triggering downstream immune responses.

    • Immunoglobulin Gene Rearrangement: Lymphocytes generate diverse antigen receptors through a process called immunoglobulin gene rearrangement. This process involves:

      • Recombination Activating Genes (RAGs): These genes are responsible for rearranging immunoglobulin gene segments.

      • Terminal deoxynucleotidyl transferase (TdT): This enzyme introduces random nucleotides, further diversifying the receptor repertoire.

    APCs and Lymphocytes

    • Antigen-Presenting Cells (APCs) activate lymphocytes in the lymph nodes
    • T helper cells (TH) are the first to demonstrate specificity
    • TH cells are required to activate B and TC cells
    • Both T and B cells create memory cells

    Antibodies

    • Antibodies have a variable region (FAB) and a constant region (FC)
    • Antibodies have different classes with varying functions
    • Antibodies can undergo class switching (e.g., IgM to IgG)
    • Active immunity occurs from exposure to an antigen through infection or vaccination
      • Natural active immunity occurs through infection
      • Artificial active immunity occurs through vaccination
    • Passive immunity occurs from receiving antibodies
      • Natural passive immunity occurs through mother to fetus or mother to infant through breast milk
      • Artificial passive immunity occurs through antibody injection

    Humoral and Cellular Immunity

    • Humoral immunity involves antibodies
      • Antibodies can guide phagocytes, activate the complement system, and neutralize free antigen
    • Cellular immunity involves cytotoxic T cells (TC)
      • TC cells directly attack antigen-bearing cells

    Complement System

    • The complement system is a complex cascade of proteins that help to destroy pathogens
    • Membrane Attack Complex (MAC) forms holes in the cell wall of microbes, leading to cell death

    How Lymphocytes Develop Specific Receptors

    • T and B cells undergo a process called immunocompetence to develop antigen receptors
    • B cells undergo immunoglobulin gene rearrangement to create unique B cell receptors
      • RAG1 and RAG2 are recombination activating genes involved in gene rearrangement
      • TdT (Terminal deoxynucleotidyl transferase) adds nucleotides during rearrangement
    • Clonal deletion or clonal inactivation eliminates cells that recognize self-antigens
      • This leads to immune tolerance

    MHC Class I and II

    • MHC I and II molecules are important in immune responses
    • MHC Class I presents endogenous antigens (produced by the body cell)
      • Involved in the activation of cytotoxic T cells (TC)
    • MHC Class II presents exogenous antigens (foreign material)
      • Involved in the activation of helper T cells (TH)

    Activation of Cytotoxic T Cells

    • TC cells recognize antigens presented by MHC I
    • TH cells (specifically TH1) assist in activating TC cells

    Checkpoint Inhibition

    • Checkpoint inhibitors regulate the immune response
    • CTLA4 and PD-1 are checkpoint inhibitors that can displace CD28 from B7, limiting activation signals

    Factors that Affect Immune Response

    • Malnutrition
    • Preexisting disease
    • Stress
    • Sleep deprivation
    • Exercise

    Immunodeficiency Diseases

    • SCID (Severe Combined Immunodeficiency Disease)
    • AIDS (Acquired Immunodeficiency Syndrome)

    Harmful Immune Responses

    • Tissue/Graft Rejection
    • Transfusion Reactions
    • Allergy (hypersensitivity)
      • Immediate hypersensitivity
      • Delayed hypersensitivity
    • Autoimmune diseases
    • Excessive Inflammatory Responses

    Other Key Factors

    • Transfusion Reactions
      • Related to ABO and Rh blood group antigens
    • Anaphylaxis
      • Severe allergic reaction resulting from widespread mast cell activation
    • Autoimmune Diseases
      • Immune system attacks self-proteins
      • Examples: Type 1 diabetes, rheumatoid arthritis, multiple sclerosis, myasthenia gravis

    Tissue Grafts and Organ Transplantation

    • MHC proteins on donor cells are foreign to the recipient
    • Drugs that kill actively dividing lymphocytes are used to prevent rejection
    • Cyclosporine blocks cytokine production from helper T cells.

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    PHGY 209 Immunology Lectures 1-2 2024 PDF
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    Description

    Explore the intricate details of the immune system, including its main components and functions. Learn about the two branches of immunity: Non-specific (Innate) and Specific (Adaptive), and the role of lymphoid organs. This quiz will enhance your understanding of how the body defends itself against pathogens.

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