J200 Exam 4 Answers – Flashcards
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| innate immunity |
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| host defenses that afford protection against any kind of pathogen |
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| adaptive immunity |
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| the ability, obtained during the life of the individual, to produce specific antibodies and T cells |
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| humoral immunity |
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| immunity brought about by antibodies |
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| bursa of Fabricius |
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| a structure resembling a lymph node, exists in birds, has no known function |
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| thymus |
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| lymphoid organ found in the upper chest, plays a role in immunity |
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| B cells |
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| recognize antigens and make specific antibodies against them |
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| T cells |
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| mature of the influence of the thymus (basis of cellular immunity) |
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| cellular immunity |
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| an immune response that involves T cells binding to an antigen presented on antigen-presenting cells; T cells then differentiate into several types of effector T cells |
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| T-cell receptors (TCRs) |
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| molecules on T cells that recognize antigens |
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| antigens |
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| any substance that causes antibody formation |
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| epitopes or antigenic determinants |
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| a specific region on the surface of an antigen against which antibodies are formed |
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| haptens |
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| a substance of low molecular weight that does not cause the formation of antibodies by itself but does so when combined with a carrier molecule |
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| antibodies |
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| globulin proteins (immunoglobulins); made in response to an antigen and can recognize and bind to an anitgen |
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| immunoglobulins (Ig) |
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| term used for antibodies |
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| anitgen-binding sites |
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| each antibody has at lease two identical binding sites |
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| valence |
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| number of antigen-binding sites on an antibody; (two binding sides = bivalent) |
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| monomer |
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| bivalent monomer has the simplest molecular structure |
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| T-dependent antigen |
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| an antigen that requires a T(subH)cell for antibody production; an antigen that will stimulate the formation of antibodies only with the assistance of T helper cells |
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| major histocompatibility complex (MHC) |
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| a collection of genes that encode molecules of genetically diverse glycoproteins that are found on the plasma membranes of mammalian nucleated cells |
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| plasma cells |
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| a cell that is an activated B cell differentiates into; plasma cells manufacture antibodies |
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| memory cells |
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| responsible for the enhanced secondary phase to an antigen |
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| clonal selection |
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| the development of clones of B and T cells against a specific antigen |
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| clonal deletion |
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| the elimination of B and T cells that react with self |
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| T-independent antigens |
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| antigens that stimulate B cells directly without the help of T cells |
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| antigen-antibody complex |
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| when an antibody encounters an antigen for which it is specific; rapidly forms |
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| affinity |
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| the strength of the bond between an antigen and an antibody |
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| specificity |
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| percentage of false positive results given by a diagnostic test |
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| agglutination |
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| antibodies cause antigens to clump together |
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| opsonization |
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| the enhancement of phagocytosis by coating microorganisms with certain serum proteins (opsonins); also called immune adherence |
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| antibody-dependent cell-mediated cytotoxicity (ADCC) |
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| the killing of antibody-coated cells by natural killer cells and leukocytes |
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| neutralization |
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| IgG antibodies inactivate microbes by blocking their attachment to host cells and they neutralize toxins in a similar manner |
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| activation of the complement system |
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| either IgG or IgM antibodies may trigger |
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| thymic selection |
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| reflects a weeding-out process; T cells that will not specifically recognize self-molecules of MHC |
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| microfold cells (M cells) |
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| intestinal cells that take up and transfer antigens to lymphocytes |
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| Peyer's patches |
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| M cells located over; secondary lymphoid organs located on the intestinal wall |
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| antigen-presenting cells (APCs) |
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| recognition of antigens by a T cell requires that they be first processed by specialized APCs |
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| T helper cells (T [subH]) |
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| a specialized T cell that often interacts with an antigen before B cells interact with the antigen |
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| T cytotoxic cells (T [subC]) |
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| a specialized T cell that destroys infected cells presenting antigens |
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| cytotoxic T lymphocyte (CTL) |
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| an activated T(subC) cell; kills cells presenting endogenous antigens |
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| CD4+ and CD8+ |
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| CDs of greatest interest |
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| clusters of differentiation (CD) |
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| T cells are also classified by certain glycoproteins on their surface |
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| T(subH)1 cells |
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| cytokines produced by mostly activate those cells related to important elements of cellular immunity, such as delayed hypersensitivity and are also responsible for activation of macrophages |
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| T(subH)2 cells |
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| produce cytokines that are associated primarily with the production of antibodies, especially IgE, that are important in allergic reactions |
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| endogenous antigens |
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| generally synthesized within the cell and are mostly of viral or parasitic origin |
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| perforin |
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| a CTL attaches to the target cell and releases pore-forming protein |
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| granzymes |
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| proteases that induce apoptosis, are then able to enter through the pore |
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| apoptosis |
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| programmed cell death |
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| T regulatory cells (T reg) |
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| subset of CD4+ helper cells and are distinguished by carrying an additional CD25 molecule; primary function is to combat autoimmunity by suppressing T cells that escape deletion in the thymus without the necessary "education" to avoid reacting against the body's self |
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| dendritic cells (DCs) |
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| characterized by long extensions called dendrites because they resemble the dendrites of nerve cells |
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| macrophages |
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| are cells usually found in a resting state |
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| activated macrophages |
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| a macrophage that has increased phagocytic ability and other functions after exposure to mediators released by T cells after stimulation by antigens |
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| natural killer (NK) cells |
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| a lymphoid cell that destroys tumor cells and virus-infected cells |
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| antibody-dependent cell-mediated cytotoxicity (ADCC) |
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| the killing of antibody-coated cells by natural killer cells and leukocytes |
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| cytokines |
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| communication required is mediated by chemical messengers called: |
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| interleukins (IL) |
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| cytokines that serve as communicators between leukocytes are known as: |
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| chemokines |
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| a family of small cytokines that induces migration of leukocytes into areas of infection or tissue damage |
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| interferons (IFN) |
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| a specific group of cytokines; alpha- and beta-IFNs are antiviral proteins produced by certain animal cells in response to a viral infection; gamma-IFN stimulates macrophage activity |
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| tumor necrosis factor (TNF) |
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| cytokines are a strong factor in inflammatory reactions of autoimmune diseases such as rheumatoid arthritis |
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| hematopoietic cytokines |
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| family of cytokines; function in controlling the pathways by which stem cells develop into different red or white blood cells |
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| cytokine storm |
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| feedback loop occasionally gets out of control, resulting in a harmful overproduction of cytokines |
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| primary response |
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| antibody production in resonse to the first contact with an antigen |
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| secondary response |
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| (or memory response or amnestic response) a rapid rise in antibody titer following exposure to an antigen after the primary response to that antigen |
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| naturally acquired active immunity |
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| develops when a person is exposed to antigens, becomes ill, and then recovers |
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| naturally acquired passive immunity |
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| involves the natural transfer of antibodies from a mother to her infant |
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| artificially acquired active immunity |
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| result of vaccination |
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| vaccination (also called immunization) |
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| process of conferring immunity by administering a vaccine |
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| vaccine |
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| a preparation of killed, inactivated, or attenuated microorganisms or toxoids to induce artificially acquired active immunity |
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| artificially acquired passive immunity |
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| involves the injection of antibodies (rather than antigens) into the body |
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| antiserum |
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| a blood-derived fluid containing antibodies |
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| serology |
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| the branch of immunology that studies blood serum and antigen-antibody reactions in vitro |
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| gamma globulin |
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| the serum fraction containing immunoglobulins (antibodies); also called immune serum globulin |
