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
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