Adaptive Immunity Lecture
29 Questions
3 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 of the following properly describes the function of antigen presenting cells (APCs)?

  • APCs release cytokines to directly kill foreign cells.
  • APCs produce antibodies to neutralize pathogens.
  • APCs phagocytose antigens and display them using Major Histocompatibility Complex. (correct)
  • APCs are synonymous with T cells.

    • What role do helper T cells play in cell-mediated immunity?

  • They are responsible for clonal selection and expansion of B cells.
  • They suppress the immune response.
  • They produce cytokines that enhance the activity of other immune cells. (correct)
  • They kill infected host cells directly.

    • Which statement about cytotoxic T cells is accurate?

  • They function by binding to antigens for clonal selection.
  • They regulate the production of antibodies.
  • They primarily produce interleukin-10.
  • They can utilize the perforin/granzyme system to eliminate cells. (correct)

    • What happens to the antigen after it is phagocytosed by an APC?

    <p>It is digested into particles for presentation.</p> Signup and view all the answers

    What is the normal range for T cell counts in healthy individuals?

    <p>600 – 1200 cells/μl</p> Signup and view all the answers

    Why do B lymphocytes utilize B cell receptors (BCR)?

    <p>To bind directly to antigens and recognize specific epitopes.</p> Signup and view all the answers

    What is the primary function of regulatory T cells (Tregs) in the immune system?

    <p>To suppress the immune response and maintain tolerance.</p> Signup and view all the answers

    In which process do antigen fragments get displayed on the surface of an APC?

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

    How does the perforin/granzyme system function in immunity?

    <p>It allows cytotoxic T cells to enter infected cells and induce apoptosis.</p> Signup and view all the answers

    What characterizes the immune response of adaptive immunity compared to innate immunity?

    <p>High specificity for antigens</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

    What is the significance of memory cells in adaptive immunity?

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

    What does the term 'clonal selection' refer to in the context of adaptive immunity?

    <p>The activation of specific lymphocytes that recognize a particular antigen.</p> Signup and view all the answers

    Which of the following is NOT a feature of adaptive immunity?

    <p>Immediate response</p> Signup and view all the answers

    During which process do T cells become activated?

    <p>Binding with antigens directly</p> Signup and view all the answers

    Which statement best describes the function of effector cells in the adaptive immune response?

    <p>They eliminate pathogens and participate in the immune response.</p> Signup and view all the answers

    What is the role of antigen presentation in adaptive immunity?

    <p>To display antigens for T cell recognition.</p> Signup and view all the answers

    Which of the following processes occurs first in the adaptive immune system?

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

    In which organ do T lymphocytes mature?

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

    Which statement accurately describes the structure of antibodies?

    <p>Antibodies are Y-shaped molecules made up of four polypeptide chains including both variable and constant regions.</p> Signup and view all the answers

    What role does the fragment crystallizable (Fc) portion of an antibody play?

    <p>It mediates physiological effects by binding to Fc receptors on cells.</p> Signup and view all the answers

    Which immunoglobulin is known for its ability to cross the placenta?

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

    How many antigen-binding sites does a typical antibody possess?

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

    What distinguishes IgA from other immunoglobulin classes?

    <p>It is the only antibody found in bodily secretions as a dimer.</p> Signup and view all the answers

    Which type of immunoglobulin accounts for 70-75% of circulating immunoglobulins?

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

    Which statement is true regarding the heavy chains in antibodies?

    <p>The type of heavy chain determines the isotype of the immunoglobulin.</p> Signup and view all the answers

    What is a characteristic feature of IgM?

    <p>It typically exists as a pentamer.</p> Signup and view all the answers

    Which immunoglobulin class is least understood and characterized by its minor presence in serum?

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

    What is the composition of the antigen-binding sites (Fab) in an antibody?

    <p>Formed from the variable regions of the heavy and light chains.</p> Signup and view all the answers

    Study Notes

    Adaptive Immunity Lecture

    • Adaptive immunity is slower than innate immunity but develops throughout a lifetime
    • It is highly specific to antigens
    • It has a memory function, meaning it adapts and improves after initial exposure to an antigen and responds more rapidly on subsequent exposure

    Adaptive Immunity: The Three Rs

    • Recognize: Each cell has a specific receptor for an antigen. Cells from the innate immune system assist with recognition. Recognition is followed by clonal selection
    • Respond: This involves cytokine secretion, antibody production, and direct cell killing.
    • Remember: Memory cells are created for a faster and stronger response on subsequent exposure to the same antigen

    Cells Involved in Adaptive Immunity

    • Lymphocytes: Include B Lymphocytes and T Lymphocytes
    • B Lymphocytes: Produce antibodies. B cells mature in the bone marrow.
    • T Lymphocytes: Involved in cell-mediated immunity. T-cells mature in the thymus.

    Clonal Selection

    • Each lymphocyte has receptors for a single antigen
    • The repertoire of lymphocytes is incredibly diverse
    • Few lymphocytes are specific to any one antigen
    • Each of these lymphocytes is highly specific
    • When an antigen binds to a lymphocyte, the lymphocyte becomes activated, and it begins to rapidly replicate, forming a clone
    • This clone differentiates into effector cells and memory cells

    Antigen Presentation

    • Antigen presenting cells (APCs) introduce antigens to T cells. APCs include phagocytes such as dendritic cells, macrophages, and neutrophils.
    • APCs use the Major Histocompatibility Complex (MHC) to display digested antigen fragments on their surface.
    • The antigen is phagocytosed by an APC
    • Fragments of the antigen are transported to the surface of the APC.
    • The antigen is displayed on the MHC Class II molecule for recognition by T cells

    T Cell Types

    • Helper T cells: Produce cytokines to enhance the activity of B cells, macrophages and other T cells
    • Cytotoxic T cells: Kill foreign cells or infected host cells, using perforin/granzyme which are proteins
    • Regulatory T cells: Suppress the immune response, produce the anti-inflammatory cytokine interleukin (IL)-10

    B Cells and Antibodies (Humoral Immunity)

    • B cell receptors (BCRs) are antibodies that bind antigens directly
    • BCRs recognize specific epitopes (antigenic determinants) on an antigen
    • Following clonal selection and expansion, B cells produce antibodies with the same specificity as their BCR

    Antibody Structure

    • Antibodies (immunoglobulins) have two identical heavy chains and two identical light chains, arranged in a Y shape
    • Each antibody has two antigen-binding sites (Fab regions)
    • The stem of the antibody (Fc region) binds to Fc receptors on cells to mediate the physiological effects of antibodies

    Antibody Isotypes

    • The five classes of antibodies are: IgG, IgM, IgA, IgD, and IgE
    • Each has different functions and characteristics
    • IgG is the most abundant in the blood
    • IgM is the first antibody produced in an immune response
    • IgA is found in secretions
    • IgD is found on the surface of B cells
    • IgE is involved in allergic responses

    Antibody Function

    • Antibodies have various functions, including neutralization of antigens/toxins, opsonization (marking pathogens for phagocytosis), antibody-dependent cellular cytotoxicity (ADCC) (targets pathogens for destruction by other cells), complement activation, and inflammation

    Primary vs. Secondary Antibody Response

    • Primary response is a slower response to an initial encounter with an antigen (5-10 days), with lower antibody titres (amounts of antibody present) and mainly IgM type
    • Secondary response to subsequent encounter is much faster (1-3 days), with higher antibody titres and mainly IgG type
    • Antibody response to second encounter is often more specific (affinity maturation)

    Immunologic Memory

    • A critical aspect of adaptive immunity
    • On a second exposure to the same antigen, the immune response is faster, more extensive, and more effective at eliminating the pathogen compared to the initial response because of memory cells

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Description

    Explore the intricacies of adaptive immunity, including its slower response time compared to innate immunity and its ability to develop a memory function. Understand the roles of lymphocytes, the three Rs (Recognize, Respond, Remember), and the specifics of B and T lymphocyte functions in immune responses.

    More Like This

    Adaptive Immunity
    20 questions

    Adaptive Immunity Quiz: Boost Your Knowledge

    IntuitiveSmokyQuartz2494 avatar
    IntuitiveSmokyQuartz2494
    Pathophysiological Concept Chapter 7: Adaptive Immunity
    15 questions

    Pathophysiological Concept Chapter 7: Adaptive Immunity

    PeaceableGreen avatar
    PeaceableGreen
    Adaptive Immunity Overview
    23 questions

    Adaptive Immunity Overview

    RobustSunflower avatar
    RobustSunflower
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser