1. Overview of the Immune System Flashcards
(21 cards)
A state of protection from an infectious disease.
Immunity
Protein consisting of two identical heavy chains and two identical light chains that recognize an epitope on an antigen and facilitate clearance of that antigen. There are five isotypes: IgA, IgD, IgE, IgG, and IgM.
Immunoglobulin
Immunoglobulin proteins consisting of two identical heavy chains and two identical light chains that recognize an antigen epitope to facilitate antigen clearance.
Antibodies
Host defenses mediated by antibodies in the plasma, lymph, and tissue fluids. It protects against extracellular bacteria and foreign macromolecules.
Humoral Immunity
Temporary adaptive immunity conferred by the transfer of immune products, such as antibody (antiserum), from an immune individual to a nonimmune one.
Passive Immunity
Adaptive immunity induced by the natural exposure to a pathogen or by vaccination.
Active Immunity
Host defenses mediated by antigen-specific T cells. It protects against intracellular bacteria, viruses, and cancer and is responsible for graft rejection. Transferring primed T cells confers this type of immunity on the recipient.
Cell-Mediated Immunity
A lymphocyte that matures in the thymus and expresses a T-cell receptor, CD3, and CD4 or CD8.
T Lymphocytes (T cells)
Lymphocytes that mature in the bone marrow and express membrane-bound antibodies. After interacting with antigen, they differentiate into antibody-secreting plasma cells and memory cells.
B Lymphocytes (B cells)
Any substance (usually foreign) that binds an antibody or a T-cell receptor; often a synonym for immunogen.
Antigens
The antigen-mediated activation and proliferation of a B cell with receptors for a target antigen (or, in the case of T cells, for MHC complexes that recognize peptides derived from the target antigen).
Clonal Selection
A disease-causing infectious agent.
Pathogens
The means by which disease-causing organisms attack a host.
Pathogenesis
A complex comprising a membrane-bound immunoglobulin molecule and two associated signal-transducing Igα,Igβ molecules.
B-cell Receptors
Antigen-binding molecule expressed on the surface of T cells and associated with the CD3 molecule. TCRs are heterodimeric, consisting of either an α and β chain or a γ and δ chain.
T-cell Receptors
A state of immunologic unresponsiveness to particular antigens or sets of antigens. Typically, an organism is unresponsive or tolerant to self antigens.
Tolerance
Nonantigen-specific host defenses that exist prior to antigen exposure and involve anatomic, physiologic, endocytic, phagocytic, antimicrobial, and inflammatory mechanisms; they do not exhibit adaptation or memory characteristics.
Innate Immunity
Host defenses mediated by B and T cells following antigen exposure; they exhibit specificity, diversity, memory, and self-nonself discrimination.
Adaptive Immunity
A localized tissue response to injury or other trauma characterized by pain, heat, redness, and swelling. The response includes both localized and systemic effects that consist of altered patterns of blood flow, an influx of phagocytic and other immune cells, removal of foreign antigens, and healing of the damaged tissue.
Inflammatory Response
The immune response following initial exposure to antigen; this response is characterized by short duration and low magnitude compared to the response that follows subsequent exposures to the same antigen
Primary Response
The immune response to an antigen that has been previously introduced and recognized by adaptive immune cells. It is mediated primarily by memory lymphocytes that have differentiated to respond more quickly and robustly to antigenic stimulation than the primary response.
Secondary Response
