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Adaptive Immunity and Antibody Function in Anatomy & Physiology

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Terms in this set (21)

  • What are the two main branches of the adaptive immune system?
    Humoral (antibody-mediated) immunity and Cellular (cell-mediated) immunity.
  • What is the primary function of humoral immunity?
    Antibodies produced by lymphocytes circulate in body fluids to temporarily inactivate and mark extracellular targets for destruction.
  • How does cellular immunity target pathogens?
    Lymphocytes act directly by killing infected cells or indirectly by releasing chemicals that enhance inflammation or activate other immune cells.
  • Define antigen and its role in adaptive immunity.
    An antigen is a substance that mobilizes adaptive defenses and provokes an immune response, usually a large, complex molecule not normally found in the body.
  • What distinguishes a complete antigen from a hapten?
    Complete antigens have immunogenicity and reactivity, while haptens are small molecules that are not immunogenic alone but can become so when attached to body proteins.
  • What are antigenic determinants?
    Specific parts of an antigen that antibodies or lymphocyte receptors bind to, allowing multiple immune responses to different parts of the same antigen.
  • What are self-antigens and their significance?
    Proteins on cell surfaces, such as MHC proteins, that are not antigenic to self but can trigger immune responses in others during transfusions or grafts.
  • What are the three crucial cell types in adaptive immunity?
    B lymphocytes (humoral immunity), T lymphocytes (cellular immunity), and antigen-presenting cells (APCs).
  • What is immunocompetence in lymphocytes?
    The ability of lymphocytes to recognize and bind to only one specific antigen via a unique antigen receptor.
  • What is self-tolerance in lymphocyte development?
    Lymphocytes must be unresponsive to the body's own antigens to prevent autoimmune reactions.
  • Describe clonal selection in lymphocytes.
    The process where a naive lymphocyte binds its specific antigen, becomes activated, proliferates, and differentiates into effector and memory cells.
  • What is the role of memory cells in adaptive immunity?
    Memory cells provide a faster and stronger immune response upon re-exposure to the same antigen.
  • What are the five major classes of antibodies?
    IgM, IgA, IgD, IgG, and IgE, each with distinct structures and immune functions.
  • What is the structure of a basic antibody molecule?
    A Y-shaped monomer with two identical heavy chains and two identical light chains, containing variable regions for antigen binding and constant regions for effector functions.
  • How do antibodies neutralize antigens?
    By blocking specific sites on viruses or toxins, preventing them from binding to host cells.
  • What is agglutination in antibody action?
    Antibodies cross-link antigens into large clumps, enhancing their removal by immune cells.
  • Explain precipitation as a mechanism of antibody action.
    Soluble antigen molecules are cross-linked into complexes that precipitate out of solution, making them easier for phagocytes to engulf.
  • What is complement fixation by antibodies?
    When antibodies bind close together on an antigen, they trigger the complement system, leading to cell lysis and enhanced immune responses.
  • What is the difference between active and passive humoral immunity?
    Active immunity involves B cells producing antibodies after antigen exposure; passive immunity involves receiving ready-made antibodies without memory formation.
  • Give examples of naturally and artificially acquired active humoral immunity.
    Naturally acquired: infection with a pathogen; Artificially acquired: vaccination with dead or attenuated pathogens.
  • Give examples of naturally and artificially acquired passive humoral immunity.
    Naturally acquired: antibodies passed from mother to fetus via placenta or milk; Artificially acquired: injection of antibody-containing serum like gamma globulin.