Skip to main content
Back

Adaptive Immunity in Microbiology

Control buttons has been changed to "navigation" mode.
1/29

Terms in this set (29)

  • What distinguishes adaptive immunity from innate immunity?
    Adaptive immunity is specific to particular antigens, takes longer to respond, and has memory, while innate immunity is immediate and nonspecific.
  • What are the two main branches of the adaptive immune system?
    Cellular response (T cell–mediated immunity) and humoral response (antibody–mediated immunity).
  • Where do T cells mature and what is their role?
    T cells mature in the thymus and play roles in both humoral and cellular immunity.
  • What is the primary function of B cells in adaptive immunity?
    B cells coordinate the humoral response by producing antibodies.
  • What are the four main stages of adaptive immune responses?
    1) Antigen presentation, 2) Lymphocyte activation, 3) Lymphocyte proliferation and differentiation, 4) Antigen elimination and memory.
  • What is an antigen?
    Any substance, mostly proteins or polysaccharides, that can trigger an immune response.
  • What factors impact an antigen's immunogenicity?
    Antigen size, molecular complexity, and chemical composition.
  • What are epitopes?
    Specific parts of an antigen recognized by B and T cells.
  • How do T cells recognize antigens?
    T cells recognize antigens presented by major histocompatibility complex (MHC) molecules using T cell receptors (TCRs).
  • What is the difference between MHC I and MHC II molecules?
    MHC I presents intracellular antigens to CD8+ cytotoxic T cells; MHC II presents extracellular antigens to CD4+ helper T cells.
  • What are the two main lineages of T cells and their markers?
    T cytotoxic cells (CD8+) and T helper cells (CD4+).
  • What is the role of helper T cells (TH cells)?
    They release cytokines to activate B cells, macrophages, and cytotoxic T cells.
  • How do cytotoxic T cells kill infected cells?
    By releasing perforins that form pores and granzymes that induce apoptosis.
  • What is clonal expansion in adaptive immunity?
    Activated B or T cells divide to produce clones that recognize the same antigen epitope.
  • What are plasma cells?
    Effector B cells that produce and secrete antibodies.
  • What are memory cells?
    Long-lived lymphocytes that provide rapid response upon re-exposure to the same antigen.
  • What are the five antibody isotypes?
    IgG, IgA, IgM, IgE, and IgD.
  • Which antibody is most abundant in blood and crosses the placenta?
    IgG.
  • What antibody is prevalent in mucous membranes and secretions?
    IgA.
  • What antibody is produced early in infection and exists as a pentamer?
    IgM.
  • Which antibody mediates allergic responses and fights parasites?
    IgE.
  • What is the difference between T-dependent and T-independent B cell activation?
    T-dependent activation requires helper T cells; T-independent activation involves repetitive antigens directly binding multiple BCRs.
  • What is isotype switching in B cells?
    The process by which B cells change the class of antibody they produce without altering antigen specificity.
  • What are the four classifications of adaptive immunity?
    Naturally acquired active, artificially acquired active, naturally acquired passive, and artificially acquired passive immunity.
  • What is the role of antigen-presenting cells (APCs)?
    APCs, like dendritic cells, engulf pathogens and present antigens to T cells to initiate adaptive immunity.
  • What is the significance of self-tolerance in adaptive immunity?
    It prevents T and B cells from attacking the body's own cells by eliminating self-reactive lymphocytes.
  • What is a superantigen?
    An antigen that non-specifically activates large numbers of T helper cells, causing excessive cytokine release and potential shock.
  • How do helper T cells influence the development of TH1 and TH2 cells?
    Cytokines IL-12 and INF-γ promote TH1 cells; IL-2 and IL-4 promote TH2 cells.
  • What is the role of interferons in viral infections?
    They recruit cytotoxic T cells and enhance MHC I production to alert the immune system.