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 (B)</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 (C)</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. (B)</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. (B)</p> Signup and view all the answers

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

<p>Cross-presentation. (C)</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. (C)</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. (B)</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. (A)</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 (A), CD8 (C)</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. (D)</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. (D)</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. (D)</p> Signup and view all the answers

Which type of lymphocyte is primarily responsible for producing antibodies?

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

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

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

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

<p>To directly kill infected cells (B)</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. (C)</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. (B)</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. (B)</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. (B)</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. (A)</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. (A)</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. (B)</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. (D)</p> Signup and view all the answers

Which of the following best defines the lymphocyte repertoire?

<p>The total collection of lymphocyte specificities. (A)</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. (C)</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. (A)</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. (B)</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. (D)</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. (C)</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. (C)</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. (B)</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. (B)</p> Signup and view all the answers

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

<p>Specificity (D)</p> Signup and view all the answers

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

<p>Diversity (B)</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 (D)</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 (C)</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. (C)</p> Signup and view all the answers

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

<p>CD 4+ T-lymphocytes (D)</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 (B)</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. (C)</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 (A)</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 (D)</p> Signup and view all the answers

Flashcards

MHC Genes

Genes that code for proteins crucial for the immune system to recognize self vs non-self.

Polymorphism

Significant variations in the DNA sequence of MHC genes.

MHC Molecules

Proteins expressed on the surface of cells, displaying antigens.

High Polymorphism of MHC

MHC molecules come in many forms.

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MHC Gene Variation

The multiple forms of genes allow the immune system to recognize a wide range of pathogens.

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MHC Polymorphism Biological Relevance

High variability of MHC genes allows the immune system to recognize a wide range of pathogens, enhancing its ability to fight infections.

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T-cell MHC Specificity

T-cell receptors (TCRs) determine if a T cell recognizes class I or class II MHC-associated peptides.

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Class I MHC

MHC class involved in presenting peptides from intracellular pathogens to cytotoxic T cells.

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Class II MHC

MHC class involved in presenting peptides from extracellular pathogens to helper T cells

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T-cell Receptor (TCR)

Molecule on T-cells responsible for recognizing specific antigens associated with MHC molecules.

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MHC presentation

The ability of a MHC molecule to display a specific antigen.

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MHC polymorphism

Multiple forms of MHC molecules to bind to antigens.

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CD4+ lymphocytes

Immune cells that help other immune cells.

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CD8+ lymphocytes

Immune cells that directly attack infected cells.

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MHC-Effector functions

Roles of MHC classes, helping CD4 & CD8 lymphocytes in immune attacks.

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MHC Molecules

Proteins on cell surfaces that display antigens to trigger immune responses.

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Class I MHC

MHC molecules that present antigens from inside cells to cytotoxic T cells.

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Class II MHC

MHC molecules that present antigens from outside cells to helper T cells.

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MHC Function

Matching antigens to lymphocytes (Helper T cells, Cytotoxic T cells) to activate the immune response.

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MHC Expression Cells

Different cells express different MHC classes; important for immune responses to various infections.

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MHC molecule role in CD4+ T cells

MHC class II molecules present antigens from extracellular pathogens to CD4+ T helper cells, activating their immune response.

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MHC molecule role in CD8+ T cells

MHC class I molecules present antigens from intracellular pathogens to CD8+ cytotoxic T cells, triggering their attack on infected cells.

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MHC class I function

Displays intracellular antigens to CD8+ T cells.

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MHC class II function

Displays extracellular antigens to CD4+ T cells.

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MHC effector function

MHC molecules' role in directing CD4+ and CD8+ T cell responses to appropriate targets.

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Effector Cells

Lymphocytes that carry out the immune response, including antibody-producing plasma cells from B-cells, cytotoxic T lymphocytes (CTLs), and helper T cells (TH cells) from T-cells.

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B-lymphocytes

Type of lymphocyte that produces plasma cells, which make antibodies to fight off pathogens.

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Cytotoxic T Lymphocytes

T-cells that directly kill infected or cancerous cells.

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T-helper cells

T lymphocytes that activate other immune cells in the response.

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Lymphocytes

A type of white blood cell central to the adaptive immune response.

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Memory cells

Long-lived lymphocytes that allow a faster secondary immune response.

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Lymphocyte repertoire

All the different types of lymphocytes and their specificities.

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Secondary immune response

A faster and stronger immune response to a previously encountered pathogen.

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Memory cells and secondary response

Differentiating lymphocytes produce these long-lived cells which allow a rapid secondary immune response.

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Lymphocyte specificities

Unique characteristics of lymphocytes enabling them to recognize and target specific pathogens.

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Specificity in Adaptive IS

Adaptive immune system's ability to recognize and target specific pathogens.

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Diversity in Adaptive IS

Adaptive immune system's wide array of receptors to recognize many different pathogens.

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Clonal Expansion in Adaptive IS

Rapid increase in the number of immune cells targeting a specific invader after recognition.

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Self-Nonself Discrimination (Adaptive IS)

Adaptive immunity's ability to recognize and ignore 'self' cells and focus attack on invaders.

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Adaptive Immunity Characteristics

Adaptive immunity is characterized by specificity, diversity, clonal expansion, and self-nonself discrimination.

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CD4+ T-cells

T cells that recognize antigens displayed by MHC class II molecules, helping other immune cells.

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CD8+ T-cells

T cells that recognize antigens displayed by MHC class I molecules, directly attacking infected cells.

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MHC class I

MHC molecules that present antigens from inside cells to CD8+ T-cells (killer T-cells).

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MHC class II

MHC molecules that present antigens from outside cells to CD4+ T-cells (helper T-cells).

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T-cell recognition rule

CD4+ T cells recognize antigens with MHC class II, while CD8+ T cells recognize antigens with MHC class I.

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Study Notes

Vision

  • The college aims to be a model for community engagement, recognized internationally for excellence in medical education, research, and health care.

Mission

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

Values

  • Islamic values
  • Excellence
  • Creativity
  • Compassion
  • 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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