Major Histocompatibility (MHC)
48 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

What is the main role of MHC class I molecules?

  • Presenting antigens to Cytotoxic T cells (correct)
  • Presenting antigens to T Helper cells
  • Transporting antigens to lymph nodes
  • Digesting pathogens for immune response
  • Which of the following cell types can function as Antigen Presenting Cells (APCs)?

  • Macrophages (correct)
  • Eosinophils
  • Neutrophils
  • Natural Killer cells
  • How do T lymphocytes recognize antigens?

  • Through presentation on the surface of cells via receptors (correct)
  • By direct interaction with floating antigens
  • By detecting changes in body temperature
  • Through contact with all immune cells
  • What is the primary function of dendritic cells in the immune response?

    <p>To transport antigens to lymph nodes</p> Signup and view all the answers

    What occurs after an antigen is processed by an Antigen Presenting Cell?

    <p>It is presented on the cell surface with MHC molecules.</p> Signup and view all the answers

    During an immune response, macrophages significantly enhance which specific immune activity?

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

    What type of antigen do MHC class I molecules primarily present?

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

    What is a key feature of the specialized receptors in Antigen Presenting Cells?

    <p>They specifically present antigens in conjunction with MHC molecules.</p> Signup and view all the answers

    Why is it crucial for most tissues to express MHC class I molecules?

    <p>To mount a T cell response against intracellular infections</p> Signup and view all the answers

    Which types of pathogens are primarily managed by Cytotoxic T cell responses?

    <p>Intracellular pathogens, especially viruses</p> Signup and view all the answers

    What role do B cells play in relation to T cells?

    <p>They present antigens to T cells for antibody responses.</p> Signup and view all the answers

    Which of the following describes intracellular antigens?

    <p>They are processed in the cytosol by the proteasome.</p> Signup and view all the answers

    What is the role of the transporter associated with antigen processing (TAP) system?

    <p>To bring processed antigens into the endoplasmic reticulum.</p> Signup and view all the answers

    How are extracellular antigens typically processed within a cell?

    <p>They undergo receptor-mediated endocytosis.</p> Signup and view all the answers

    What is a key difference between how intracellular and extracellular antigens are presented?

    <p>Intracellular antigens are presented on MHC 1, while extracellular antigens utilize MHC 2.</p> Signup and view all the answers

    Which mechanism is involved in transporting MHC molecules to the cell surface after the fusion of vesicles containing antigens?

    <p>Transport vesicle movement.</p> Signup and view all the answers

    What characterizes extracellular antigens?

    <p>They come from bacteria, parasites, and fungi that do not replicate inside cells.</p> Signup and view all the answers

    In the presentation of antigens on MHC molecules, which structure contains pre-formed MHC 2 molecules?

    <p>Golgi complex.</p> Signup and view all the answers

    Which statement best describes the processing pathway of intracellular antigens?

    <p>They are processed by the proteasome before interacting with MHC molecules.</p> Signup and view all the answers

    Which immune response type is primarily activated by MHC 1 molecules?

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

    Match the following types of MHC molecules with their primary T cell interactions:

    <p>MHC class I = Antigen Presenting Cells MHC class II = Macrophages</p> Signup and view all the answers

    Match the following immune cells with their respective locations:

    <p>Macrophages = Skin and mucosal surfaces Dendritic cells = Regional draining lymph nodes B cells = Bone marrow T cells = Peripheral blood</p> Signup and view all the answers

    Match the following antigen processing functions to the respective immune cells:

    <p>Macrophages = Phagocytosis and cytokine release Dendritic cells = Antigen transport to lymph nodes B cells = Antigen recognition and antibody production Cytotoxic T cells = Destruction of infected cells</p> Signup and view all the answers

    Match the following pathogens with their primary immune targets:

    <p>Viruses = MHC class I molecules Bacteria = Antigen Presenting Cells Fungi = Cytotoxic T cells Parasites = T Helper cells</p> Signup and view all the answers

    Match the following descriptions with the correct MHC molecule type:

    <p>MHC class I = Found on almost all nucleated cells MHC class II = Found on professional APCs</p> Signup and view all the answers

    Match the cells to their roles in antigen presentation:

    <p>Macrophages = Enhance phagocytosis Dendritic cells = Activate T cell responses B cells = Produce antibodies Cytotoxic T cells = Kill infected cells</p> Signup and view all the answers

    Match the immune response activity with the respective immune components:

    <p>Cytotoxic T cells = Targeting infected cells T Helper cells = Activation of other immune cells Antigen Presenting Cells = Antigen processing and presentation Cytokines = Regulation of immune responses</p> Signup and view all the answers

    Match the following characteristics with the correct type of antigen:

    <p>Intracellular antigens = Present in virus-infected cells Extracellular antigens = Found in body fluids Peptides = Result from antigen digestion Carbohydrates = Often a component of bacterial structure</p> Signup and view all the answers

    Match the following immune processes with their descriptions:

    <p>Antigen uptake = Digestion into smaller fragments MHC transport = Bringing antigen-MHC complex to cell surface T cell activation = Recognition of MHC-antigen complex Cytokine release = Enhances immune response efficiency</p> Signup and view all the answers

    Match the following types of antigens with their characteristics:

    <p>Intracellular Antigens = Presented by MHC class I molecules Extracellular Antigens = Brought into cells by receptor-mediated endocytosis</p> Signup and view all the answers

    Match the following processes with their associated antigens:

    <p>Proteasome processing = Intracellular antigens Endocytosis = Extracellular antigens MHC class I presentation = Intracellular antigens MHC class II presentation = Extracellular antigens</p> Signup and view all the answers

    Match the following components with their functions:

    <p>TAP system = Transports peptides to the endoplasmic reticulum Golgi complex = Contains pre-formed MHC class II molecules Transport vesicle = Moves MHC molecules to the cell surface Vesicle fusion = Combines antigen-containing and MHC-containing vesicles</p> Signup and view all the answers

    Match the following cells with their antigen-related functions:

    <p>B cells = Produce antibodies upon T cell activation Dendritic cells = Primarily activate T cells Macrophages = Enhance immune responses</p> Signup and view all the answers

    Match the following types of antigens to the pathogens they are associated with:

    <p>Intracellular antigens = Certain intracellular bacteria Extracellular antigens = Non-replicating pathogens</p> Signup and view all the answers

    Match the process with the correct step in antigen processing:

    <p>Vesicle fusion with Golgi = For extracellular antigens Cytosolic processing = For intracellular antigens TAP transport = Delivers peptides to MHC class I Endocytosis mechanism = For bringing extracellular antigens in</p> Signup and view all the answers

    Match the following terms with their descriptions:

    <p>MHC class I molecules = Present intracellular antigens MHC class II molecules = Present extracellular antigens Transport vesicles = Deliver antigens to the cell surface Proteasome = Processes intracellular proteins for antigen presentation</p> Signup and view all the answers

    Match the following steps in the immune response with their roles:

    <p>Antigen presentation = T cell activation Antibody production = B cell response Intracellular antigen processing = Involves the proteasome Extracellular antigen processing = Involves receptor-mediated endocytosis</p> Signup and view all the answers

    Match the following processes with their associated cellular structures:

    <p>Endoplasmic reticulum = Where MHC class I molecules bind peptides Golgi apparatus = Packages MHC class II molecules Cytosol = Site of intracellular antigen processing Cell surface = Location for the display of processed antigens</p> Signup and view all the answers

    What is the primary function of Class 2 antigen-presenting cells?

    <p>Stimulate phagocytosis and present antigen to T Helper</p> Signup and view all the answers

    Which class of MHC molecules is associated with presenting antigens to Cytotoxic T cells?

    <p>Class 1 MHC molecules</p> Signup and view all the answers

    Which of the following antigen-presenting cells is known to take in surface immunoglobulin (Ig) and antigen?

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

    What characteristic distinguishes dendritic cells from other antigen-presenting cells?

    <p>They bring and present antigens to T Helper cells in lymph nodes.</p> Signup and view all the answers

    Which type of antigen-presenting cell is capable of phagocytosis?

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

    Match the MHC class with its primary function:

    <p>Class 1 = Stimulates Cytotoxic T cell immune response Class 2 = Stimulates antibody secretion by B cell line</p> Signup and view all the answers

    Match the cell type with its phagocytic ability:

    <p>All = No Macrophage = Yes Dendritic = Yes, in tissues B cell = Yes, takes in surface Ig and antigen</p> Signup and view all the answers

    Match the cell type with its MHC class:

    <p>Macrophage = Class 2 Dendritic = Class 2 B cell = Class 2 All = Class 1</p> Signup and view all the answers

    Match the antigen-presenting cell with its primary location for presenting antigens:

    <p>Dendritic = Lymph nodes Macrophage = Primary infection site B cell = Lymph nodes All = Throughout the body</p> Signup and view all the answers

    Match the antigen-presenting cell with its function:

    <p>Macrophage = Stimulates phagocytosis and presents antigen Dendritic = Brings antigen to T Helper B cell = Stimulates antibody secretion All = Stimulates Cytotoxic T cell immune response</p> Signup and view all the answers

    Study Notes

    T Cell Antigen Recognition

    • T lymphocytes recognize antigens only when presented by MHC molecules on the surface of cells.

    • MHC Class I and MHC Class II molecules are responsible for antigen presentation to T cells.

    • MHC I presents processed antigen to Cytotoxic T cells.

    • MHC II presents processed antigen to T Helper cells.

    Antigen Presenting Cells (APCs)

    • Three professional APCs exist: macrophages, dendritic cells, and B cells.

    • APCs process antigens by breaking them down and presenting them on their MHC II molecules.

    • APCs activate an immune response by presenting antigens to T Helper cells.

    MHC Class 1: Intracellular Antigen Presentation

    • All cells express MHC I molecules to present intracellular antigens, primarily from viral infections.

    • MHC I molecules with bound antigen stimulate Cytotoxic T cells to destroy infected cells.

    • This process facilitates the clearance of intracellular pathogens, especially viruses.

    MHC Class 1: Cellular Functions

    • Macrophages release cytokines which enhance phagocytosis.

    • Dendritic cells bring antigens to lymph nodes, where T cell responses are mounted.

    • Macrophages reside in the skin, nasopharynx, stomach, lungs, and intestines.

    • B cells can present antigens to T cells, crucial for specific antibody responses.

    Intracellular and Extracellular Antigen Processing

    • Intracellular antigens, typically from viruses and intracellular bacteria, are processed in the cytosol by the proteasome, transported to the endoplasmic reticulum via TAP, and then presented through MHC I.

    • Extracellular antigens are engulfed by endocytosis, fuse with Golgi vesicles containing MHC II, and are ultimately presented by MHC II on the cell surface.

    T Cell Recognition

    • T lymphocytes do not recognize free-floating antigens or antigens on pathogen surfaces.
    • T cells specifically recognize antigens presented on the surface of cells by Major Histocompatibility Complex (MHC) molecules.

    MHC Molecules

    • MHC class I and MHC class II molecules are involved in antigen presentation.
    • Both MHC classes process antigens and transport them to the cell surface.
    • MHC class I presents antigens to cytotoxic T cells.
    • MHC class II presents antigens to T helper cells.

    Antigen Presenting Cells (APCs)

    • Macrophages, dendritic cells, and B cells are professional APCs.
    • APCs possess MHC class II receptors and present antigens to T helper cells, initiating an immune response.
    • APCs engulf antigens and process them by breaking them down into smaller fragments.
    • These fragments are then presented on the cell surface bound to MHC molecules.
    • The combination of MHC and antigen fragment is recognized by the T cell receptor.
    • Several cell types express MHC I to present intracellular antigens.
    • This facilitates recognition by cytotoxic T cells, leading to the destruction of infected cells.
    • MHC I expression is crucial for combating intracellular pathogens, especially viruses.

    APC Functions

    • Macrophages stimulate T cells to release cytokines that enhance phagocytosis.
    • Dendritic cells phagocytose pathogens and transport antigens to lymph nodes.
    • Lymph nodes are crucial sites for T cell responses against pathogens in interstitial tissues.
    • B cells can present antigens to T cells, contributing to antibody responses.

    Intracellular vs. Extracellular Antigens

    • Intracellular antigens, often from viruses or intracellular parasites, are processed in the cytosol by the proteasome.

    • These antigens are then transported to the endoplasmic reticulum by the transporter associated with antigen processing (TAP).

    • Inside the endoplasmic reticulum, they associate with MHC I molecules and are transported to the cell surface.

    • Extracellular antigens, typical of bacteria, parasites, and fungi, are internalized by receptor-mediated endocytosis.

    • The resulting vesicles fuse with Golgi vesicles containing pre-formed MHC II molecules.

    • This fusion leads to the association of antigen and MHC II, followed by transport to the cell surface.

    Antigen-Presenting Cells (APCs)

    • APCs present antigens to T cells to trigger an immune response.
    • APCs express MHC molecules on their surface.
    • MHC class I is expressed by all cells and presents antigens to cytotoxic T cells.
    • MHC class II is expressed by macrophages, dendritic cells, and B cells.
    • Macrophages are phagocytic and engulf pathogens.
    • They present antigens to T helper cells at the site of infection.
    • Dendritic cells are phagocytic in tissues and migrate to lymph nodes to present antigens to T helper cells.
    • B cells can internalize antigens via their surface immunoglobulin receptors and present them to T helper cells to trigger antibody secretion.

    Antigen-presenting Cells - MHC Class One

    • All cells present MHC class one molecules
    • MHC class one does not engage in phagocytosis
    • Presents antigen to cytotoxic T cells
    • Triggers cytotoxic T cell responses

    Antigen-presenting Cells - MHC Class Two

    • MHC class two molecules are expressed on macrophages, dendritic cells, and B cells
    • Macrophages engulf and destroy pathogens through phagocytosis
    • Macrophages present antigens to T helper cells at the site of infection
    • Dendritic cells phagocytose in tissues
    • Dendritic cells then migrate to lymph nodes and present antigen to T helper cells
    • B cells present antigen to T helper cells
    • B cells internalize antigens via surface immunoglobulin
    • B cells undergo differentiation and promote antibody secretion

    Studying That Suits You

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

    Quiz Team

    Description

    This quiz covers the fundamentals of T cell antigen recognition and the role of MHC molecules in immune responses. It explores how MHC Class I and Class II present antigens to Cytotoxic and T Helper cells, and the function of Antigen Presenting Cells in activating an immune response. Test your knowledge on these vital immunological concepts.

    More Like This

    Use Quizgecko on...
    Browser
    Browser