Immunology Antigen Presentation Quiz
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Questions and Answers

What is the primary role of MHC Class I molecules in T-lymphocyte activation?

  • To activate all types of T-lymphocytes simultaneously
  • To present antigens exclusively to CD4+ lymphocytes
  • To enhance antibody production in B cells
  • To present intracellular antigens to CD8+ lymphocytes (correct)

    • How does MHC polymorphism benefit the survival of a species?

  • By limiting the types of antigens that can be presented
  • By ensuring all individuals can present the same antigens
  • By allowing a diverse range of MHC molecules to present various antigens (correct)
  • By promoting the activation of CD8+ lymphocytes only

    • Which T-lymphocyte subset primarily interacts with MHC Class II molecules?

  • CD8+ lymphocytes
  • Memory T cells
  • CD4+ lymphocytes (correct)
  • Regulatory T cells

    • What mechanism allows antigen presenting cells (APCs) to present extracellular antigens to CD8+ T lymphocytes?

    <p>Cross-presentation via MHC Class I</p> Signup and view all the answers

    What characteristic of MHC Class I structures is crucial for their function?

    <p>The ability to bind a wide range of peptides from endogenous sources</p> Signup and view all the answers

    What characteristic of MHC genes contributes to their ability to present a diverse array of peptides?

    <p>They are highly polymorphic.</p> Signup and view all the answers

    Which of the following best describes the structural differences between MHC Class I and MHC Class II molecules?

    <p>MHC Class I consists of a single chain, whereas MHC Class II consists of two different chains.</p> Signup and view all the answers

    What mechanism allows for the presentation of extracellular antigens by MHC Class I molecules?

    <p>Cross-presentation.</p> Signup and view all the answers

    What is the primary role of antigen-presenting cells (APCs) in the immune response?

    <p>To process and present antigens to T cells.</p> Signup and view all the answers

    Why is the polymorphism of MHC molecules important for the immune system?

    <p>It allows for enhanced recognition of diverse pathogens.</p> Signup and view all the answers

    What is the primary biological relevance of extreme polymorphism in MHC molecules?

    <p>It increases the likelihood of diverse antigen presentation.</p> Signup and view all the answers

    Which molecules on T-lymphocytes are specifically involved in recognizing class I MHC-associated peptide antigens?

    <p>TCR alpha and beta</p> Signup and view all the answers

    How does cross-presentation by antigen presenting cells (APCs) enhance T-lymphocyte activation?

    <p>By enabling APCs to present exogenous antigens on class I MHC.</p> Signup and view all the answers

    What role do class II MHC molecules play in T-lymphocyte activation?

    <p>They present antigens to CD4 helper T-cells.</p> Signup and view all the answers

    What is a consequence of the polymorphism of MHC molecules in the context of immune response?

    <p>Enhanced capacity of the immune system to recognize various pathogens.</p> Signup and view all the answers

    Which type of lymphocyte is primarily responsible for producing antibodies?

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

    Which cells are classified as effector cells in the immune response?

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

    What is the function of cytotoxic lymphocytes in the immune response?

    <p>To directly kill infected cells</p> Signup and view all the answers

    What role do T-helper cells play in the immune response?

    <p>They assist other immune cells in their functions.</p> Signup and view all the answers

    Which of the following statements is true regarding effector cells?

    <p>Effector cells include both B and T lymphocytes.</p> Signup and view all the answers

    What distinguishes the functions of CD4+ lymphocytes from CD8+ lymphocytes in relation to MHC molecules?

    <p>CD4+ lymphocytes primarily recognize MHC Class II molecules.</p> Signup and view all the answers

    How do CD8+ lymphocytes utilize MHC Class I molecules in their effector functions?

    <p>To directly kill virus-infected or cancer cells.</p> Signup and view all the answers

    Which statement accurately describes the role of MHC Class II molecules?

    <p>They are essential for presenting extracellular antigens.</p> Signup and view all the answers

    In what way does the interaction between T-lymphocytes and MHC molecules enhance immune response?

    <p>It ensures the activation and differentiation of T-lymphocytes.</p> Signup and view all the answers

    What is a unique feature of MHC Class I molecules that supports their function?

    <p>They present endogenous antigens derived from the cell's own proteins.</p> Signup and view all the answers

    What is the primary function of memory cells in the immune response?

    <p>They are responsible for the secondary immune response.</p> Signup and view all the answers

    Which of the following best defines the lymphocyte repertoire?

    <p>The total collection of lymphocyte specificities.</p> Signup and view all the answers

    Which statement is true regarding the differentiation of lymphocytes?

    <p>Some lymphocytes become long-lived cells responsible for secondary responses.</p> Signup and view all the answers

    What is a characteristic feature of memory lymphocytes?

    <p>They provide a faster response upon re-exposure to the same antigen.</p> Signup and view all the answers

    What happens to lymphocytes after they differentiate into memory cells?

    <p>They remain dormant but can respond to antigens later.</p> Signup and view all the answers

    What is a major biological characteristic of MHC molecules?

    <p>MHC molecules display peptide fragments on the cell surface to T-lymphocytes.</p> Signup and view all the answers

    Which cells predominantly express MHC Class II molecules?

    <p>Antigen-presenting cells such as dendritic cells, macrophages, and B-cells.</p> Signup and view all the answers

    How does the diversity of MHC molecules affect the immune response?

    <p>It enhances the ability to present a wider array of peptide antigens to T-lymphocytes.</p> Signup and view all the answers

    What functional characteristic distinguishes MHC Class I molecules from Class II?

    <p>MHC Class I molecules present intracellular antigens, whereas Class II present extracellular antigens.</p> Signup and view all the answers

    Which of the following correctly describes the role of antigen-presenting cells (APCs) in relation to MHC molecules?

    <p>APCs express MHC molecules that allow for T-lymphocyte activation through antigen presentation.</p> Signup and view all the answers

    What characteristic of adaptive IS ensures that specific keys fit only one lock?

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

    Which characteristic of adaptive IS indicates the presence of multiple distinct locks for different keys?

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

    What does the term 'Clonal Expansion' refer to in the context of adaptive IS?

    <p>The process of amplifying specific immune cells in response to an antigen</p> Signup and view all the answers

    Which feature of adaptive IS prevents it from attacking the body's own cells?

    <p>Non-reactivity to Self</p> Signup and view all the answers

    How does the characteristic of specificity in adaptive IS affect its response to antigens?

    <p>It guarantees a perfect fit between each antigen and its corresponding receptor.</p> Signup and view all the answers

    What type of T-lymphocytes recognize antigens with MHC II molecules?

    <p>CD 4+ T-lymphocytes</p> Signup and view all the answers

    Which T-lymphocyte subtype is primarily responsible for interacting with MHC I molecules?

    <p>CD 8+ T-lymphocytes</p> Signup and view all the answers

    What is the main distinguishing feature of CD 4+ T-lymphocytes in relation to antigen recognition?

    <p>They specifically recognize antigens presented on MHC II molecules.</p> Signup and view all the answers

    Which of the following can CD 8+ T-lymphocytes bind to during immune response?

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

    Which T-lymphocyte type is essential for assisting other immune cells in antigen recognition?

    <p>CD 4+ T-lymphocytes</p> Signup and view all the answers

    Study Notes

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    Mission

    • To raise standards in medical education, health care, research, and community health services.

    Values

    • Islamic values
    • Excellence
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    • Leadership
    • Responsiveness to community

    Antigen Presentation Course Details

    • Course Title: Antigen Presentation
    • CRN: 15569 (Male), 15581 (Female)
    • Block: 1.2
    • Subject/Discipline: Immunology
    • Expert: Dr. Sayed A. Quadri
    • Block Coordinator: Dr. Sayed A. Quadri

    Learning Objectives

    • Explain how T and B lymphocytes recognize antigens.

    • Explain why the immune system requires a specialized system of antigen presentation for effective immune responses.

    • Identify the molecules that play a crucial role in antigen presentation to T lymphocytes.

    • Describe the cell types involved in capturing invading microorganisms and their roles.

    • Explain how CD8+ T-lymphocyte responses are initiated by dendritic cells and define "cross-presentation".

    • Describe the molecular structure of MHC class I and class II molecules, including their biological and functional characteristics, and the cells that express them.

    • Explain how peptides originating from proteins outside the cell are absorbed by MHC class II molecules, the role of CLIP peptide, proteins of intracellular origin presented by MHC class I molecules, and the role of TAT proteins in this.

    • Explain the biological relevance of the extreme polymorphism of MHC molecules.

    • Identify the molecules on T lymphocytes that contribute to their specificity for class I or class II MHC-associated peptide antigens.

    • Explain the roles of MHC classes I and II in effector functions of CD4+ and CD8+ lymphocytes

    • Define MHC molecules as Major Histocompatibility Complex, including proteins on cells. Identify Antigen Presenting Cells (APCs). Define Naïve T-lymphocytes as T-cells that haven't encountered antigen.

    • Explain the significance of co-stimulation and co-stimulatory signals for T-cell activation.

    • Discuss Lymphocyte repertoire as the total collection of lymphocytes' specificities, including specificity, diversity, clonal expansion, and non-reactivity to self.

    • Introduce Rule 1: Each lymphocyte clone has a unique antigen receptor specific to a particular antigen.

    • Introduce the concepts of clonal expansion (increase in numbers of a specific lymphocyte) and cytokines (proteins released by cells that act upon other cells, paracrine or endocrine).

    • Describe the differentiation of lymphocytes, their function as effectors generating an immune response (antibody production from B cells cytotoxic lymphocytes (CTLs) and T-helper cells (TH cells)), and the role of memory cells in secondary immune responses.

    Terms to be Familiar

    • MHC molecules, proteins on cell surfaces
    • Antigen-presenting cells (APCs)
    • Naïve T lymphocytes
    • Co-stimulation and co-stimulatory signals

    Key Terms - Continuing

    • Clonal expansion
    • Cytokines
    • Lymphoid organs
    • Lymphocyte recirculation
    • Lymphocyte differentiation.
    • Total collection of lymphocyte specificities
    • Antigen Specific Lymphocytes
    • Specificity
    • Diversity
    • Clonal Expansion
    • Non-reactivity to Self
    • Antigens
    • Lymphocytes
    • Lymphocyte repertoire
    • MHC restriction
    • Antigen presenting cells (APC)
    • Major Histocompatibility Complex (MHC)
    • T-Lymphocytes
    • T-cell Receptor (TCR)
    • MHC I
    • MHC II
    • CD4+
    • CD8+

    Antigen Recognition

    • B-lymphocytes recognize antigens by membrane-bound antibodies on their surface.
    • B-lymphocytes recognize a variety of antigens (proteins, polysaccharides, fats, and nucleic acids). They recognize directly.
    • T-lymphocytes recognize antigens by the peptide antigen bound to the MHC on APCs (antigen-presenting cells).
    • T-lymphocytes recognize antigen in bond with antigen-presenting cell (APC).

    Rule 2

    • T lymphocytes recognize antigen when presented by another cell with MHC on its surface.

    Why Specialized Antigen Presentation?

    • Antigens can enter through any body site. Antigen-specific lymphocytes are rare (one in a million).
    • Different types of antigens may require distinct responses.
    • The immune system must respond to the same microbe in different ways at different stages of infection.

    Cell Capture, Processing, and Presentation

    • Dendritic cells capture antigens in various ways.
    • Cells (Dendritic cells) migrate to lymph nodes and present antigen to T lymphocytes.
    • Capture → Process → Present.

    MHC Class Pathways

    • Diagrammatic details of MHC Class I and Class II pathways are provided.

    What Kind of Molecules

    • MHC class II molecules are critical in antigen presentation to T lymphocytes.

    Molecules Critical for Antigen Presentation (Summary)

    • MHC molecules (present on cell surfaces) are essential. The complex of antigen bound to MHC is displayed on the surface of antigen-presenting cells.
    • T-lymphocytes only recognize antigen when displayed with MHC on an APC.
    • Each individual's MHC is unique; T lymphocytes only recognize antigen with the MHC of the same individual. MHC restriction.
    • T lymphocytes recognize antigen by TCR.

    Different T-Cell Types

    • CD4+ T-lymphocytes recognize antigen with MHC II.
    • CD8+ T-lymphocytes recognize antigen with MHC I.

    Biological Relevance of MHC Polymorphism (Explanation)

    • MHC polymorphism is essential for antigen presentation.
    • It ensures survival of the species as multiple individuals have MHC that can present a particular antigen.

    Roles of MHC in Effector Functions

    • CD4+ and CD8+ lymphocytes utilize MHC molecules in effector functions involving antigen uptake or synthesis.

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    Antigen Presentation 2022-23 Past Paper PDF

    Description

    Test your knowledge on antigen presentation in immunology. This quiz covers the recognition of antigens by T and B lymphocytes, the specialized system of antigen presentation, and the key molecules and cell types involved. Challenge yourself to deepen your understanding of these critical immune responses.

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