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| the kind of defense that is mediated by phagocytic cells, antimicrobial proteins, the inflammatory response, and natural killer cells. It is present before exposure to pathogens and is effective from the time of birth |
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| The kind of defense that is mediated by B cells and T cells. It exhibits specificity, memory, and self-nonself recognition. |
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| a type of white blood cell that mediates acquired immunity. Lymphocytes that complete their development in the bone marrow are called B cells, and those that mature in the thymus are called T cells |
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| A protein secreted by plasma cells that binds to a particular antigen and marks it for elimination. All antibody molecules have the same Y-shaped structure and in their monomer form consist of two identical heavy chains and two identical light chains joined by disulfide bridges |
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| an enzyme in sweat, tears, and saliva that attacks bacterial walls |
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| a type of endocytosis involving large, particulate substances, accomplished mainly by macrophages, neutrophils, and dendritic cells |
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| the most abundant type of white blood cell. Neutrophils are phagocytic and tend to self-destruct as they destroy foreign invaders. limiting their life span to a few days |
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| a phagocytic cell present in many tissues that functions in innate immunity by destroying microbes and in acquired immunity as an antigen-presenting cell |
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| a type of white blood cell that migrates into tissues and develops into a macrophage |
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| a type of white blood cells with low phagocytic activity that is thought to play a role in defense against parasitic worms by releasing enzymes toxic to those invaders |
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| an antigen-presenting cell, located mainly in lymphatic tissues and skit, that is particularly efficient in presenting antigens to naive helper T cells, thereby initiating a primary immune response |
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| a group of about 30 blood proteins that may amplify the inflammartory response, enhance phagocytosis, or directly lyse pathogens. The complement system is activated in a cascade initiated by surface antigens on microorganisms or by antigen-antibody complexes |
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| a protein that has antiviral of immune regulatory functions. Interferon alpha and interferon beta, secreted by virus-infected cells, help nearby cells resist viral infection; interferon sigma, secreted by T cells, helps activate macrophages |
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| a localized innate immune defense triggered by physical injury or infection of tissue in which changes to nearby small blood vessels enhance the infiltration of white blood cells, antimicrobial proteins, and clotting elements that aid in tissue repair and destruction of invading pathogens may also involve systemic effects such as fever and increased production of white blood cells |
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| a substance released by mast cells that causes blood vessels to dilate and become more permeable during an inflammatory response |
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| a vertebrate body cell that produces histamine and other molecules that trigger the inflammatory response |
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| any of about 50 different proteins, secreted by many cell types near a site of injury or infection, that help direct migration of white blood cells to an injury site and induces other changes central to inflammation |
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| a type of white blood cell that can kill tumor cells and virus-infected cells; an important component of innate immunity |
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| The changes that occur within a cell as it undergoes programmed cell death, which is brought about by signals that trigger the activation of a cascade of suicide proteins in the cell destined to die |
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| any of a group of proteins secreted by a number of cell types, including macrophages and helper T cells, that regulate the function of lymphocytes and other cells of the immune system |
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| a macromolecule that elicits an immune response by lymphocytes |
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| a small, accessible region of an antigen to which an antigen receptor or antibody binds |
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| a type of lymphocyte that develops to maturity in the bone marrow. After encountering antigen, B cells differentiate into antibody-secreting plasma cells, the effector cells of humoral immunity |
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| a type of lymphocyte, including the helper T cells and cytotoxic T cells, that develops to maturity in the thymus. After encountering antigen, T cells are responsible for cell-mediated immunity |
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| The general term for a surface protein, located on B cells and T cells, that binds to antigens, initiating acquired immune responses. |
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| the antigen receptor on B cells; a Y-shaped, membrane-bound molecule consisting of two identical heavy chains and two identical light chains linked by disulfide bridges and containing two antigen-binding sites |
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Definition
| one of the two types of polypeptide chains that make up an antibody molecule and B cell receptor; consists of a variable region, which contributes to the antigen-binding site, and a constant region |
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| one of the two types of polypeptide chains that make up an antibody molecule and B cell receptor; consists of a variable region, which contributes to the antigen-binding site, and a constant region |
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| any of the class of proteins that function as antibodies. Immunoglobulins are divided into five major classes that differ in their distribution in the body and antigen disposal activities |
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| the antigen receptor on T cells; a membrane-bound molecule consisting of one alpha chain and one beta chain linked by a disulfide bridge and containg one antigen binding site |
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| major histocompatibility complex (MHC) |
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Definition
| a family of genes that encode a large set of cell surface proteins called MHC molecules. Class 1 and class 2 MHC molecules function in antigen presentation to T cells. Foreign MHC molecules on transplanted tissue can trigger T cell responses that may lead to rejection of the transplant |
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| The process by which an MHC molecule binds to a fragment of an intracellular protein antigen and carries it to the cell surface, where it is displayed and can be recognized by a T cell. |
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| a collection of cell surface proteins encoded by a family of genes called the MHC. Class 1 MHC molecules are found on nearly all nucleated cells |
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| a type of lymphocyte that, when activated, kills infected cells, cancer cells, and transplanted cells |
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| a collection of cell surface proteins encoded by a family of genes called the MHC. Class 2 MHC molecules are restricted to a few specialized cell types, commonly called antigen-presenting cells |
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| a cell that ingests bacteria and viruses and destroys the, generating peptide fragments that are bound by class 2 MHC molecules and subsequently displayed on the cell surface to helper T cells. Macrophages, dendritic cells, and B cells are the primary antigen-presenting cells. |
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Definition
| a small organ in the thoracic cavity of vertebrates where maturation of T cells is completed |
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| a muscle cell or gland cell that performs the body's responses to stimuli; responds to signals from the brain or other processing center of the nervous system. |
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Definition
| one of a clone of long-lived lymphocytes, formed during the primary immune response, that remains in a lymphoid organ until activated by exposure to the same antigen that triggered its formation. Activated memory cells mount the secondary immune response |
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Definition
| the process by which an antigen selectively binds to and activates only those lymphocytes bearing receptors specific for the antigen. The selected lymphocytes proliferate and differentiate into a clone of effector cells and a clone of memory cells specific for the stimulating antigen. Clonal selection accounts for the specificity and memory of acquired immune responses. |
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Definition
| the initial acquired immune response to an antigen, which appears after a lag of about 10 to 17 days |
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Definition
| the antibody-secreting effector cell of humoral immunity; arises from antigen-stimulated B cells |
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| secondary immune response |
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Definition
| the acquired immune response elicited on second or subsequent exposures to a particular antigen. The secondary immune response is more rapid, of greater magnitude, and of longer duration than the primary immune response |
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Definition
| the branch of acquired immunity that involves the activation of B cells and the leads to the production of antibodies, which defend against bacteria and viruses in body fluids |
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| cell-mediated immune response |
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Definition
| the branch of acquired immunity that involves the activation of cytotoxic T cells, which defend against infected cells, cancer cells, and transplanted cells |
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| a type of T cell that, when activated, secretes cytokinds that promost the response of B cells and cytotoxic T cells to antigens |
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Definition
| a surface protein , present on most helper T cells, that binds to class 2 MHC molecules on antigen-presenting cells, enhancing the interaction between the T cell and the antigen-presenting cell |
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Definition
| a surface protein, present of most cytotoxic cells, that bind to class 1 MHC molecules on target cells, enhancing the interaction between the T cell and the target cell |
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Definition
| any of a preparation of antibodies that have been produced by a single clone of cultured cells and thus are all specific for the same epitope |
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| Membrane attack complex (MAC) |
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Definition
| a molecular complex consisting of a set of complement proteins that forms a pore in the membrane of bacterial and transplanted cells, causing the cells to die by lysis |
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Definition
| long-lasting immunity conferred by the action of a person's B cells and T cells and the resulting B and T memory cells specific for a pathogen. Active immunity can develop as a result of natural infection or immunization |
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Definition
| the process of generating a state of immunity by artificial means. In active immunization, a nonpathogenic version of a normally pathogenic microbe is administered, inducing B and T cell responses and immunological memory. In passive immunization, antibodies specific for a particular microbe are administered, conferring immediate but temporary protection |
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Definition
| short-term immunity conferred by the administration of ready-made antibodies or the transfer of maternal antibodies to a fetus or nursing infant; lasts only a few weeks or months because the immune system has not been stimulated by antigens |
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Definition
| a protein antigen on the surface of red blood cells designated Rh-positive. If an Rh-negative mother is exposed to blood from an Rh-positive fetus, she produces anti-Rh antibodies of the IgG class |
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| graft versus host reaction |
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Definition
| an attack against a patient's body cells by lymphocytes received in a bone marrow transplant |
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Definition
| an acute, whole-body, life-threatening allergic response |
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| an immunological disorder in which the immune system turn against itself |
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Definition
| the name of the late stages of HIV infection, defined by a specified reduction of T cells and the appearance of characteristic secondary infections |
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Definition
| the infectious agent that causes AIDS. HIV is a retrovirus |
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Definition
-skin, mucous membranes, secretions
-phagocytic cells, antimicrobial proteins, inflammatory response, natural killer cells |
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Term
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Definition
1) pseudopodia surround microbes
2) microbes are engulfed into cell
3) vacuole containing microbes forms
4) vacuole and lysosome fuse
5) toxic compounds and lysosomal enzymes destroy microbes
6) microbial debris is released by exocytosis |
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Term
| the human lymphatic system |
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Definition
1) interstatial fluid continually enters lymphatic capillaries
2) lymph flows through lymphatic vessels throughout the body
3) within lymph nodes, microbes and foreign particles encounter macrophages, dendritic cells, and lymphocytes
4)lymphatic vessels return lymph to the blood via two large ducts that drain into veins near the shoulders. |
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| major events in the local inflammatory response |
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Definition
1) chemical signals released by activated macrophages and mast cells at the injury site cause nearby capillaries to widen and become more permeable.
2) fluid, antimicrobial proteins, and clotting elements move from the blood to the site. Clotting begins
3) chemokines released by various kinds of cells attract more phagocytic cells from the blood to the injury site
4) neutrophils and macrophages phagocytose pathogens and cell debris at the site and the tissue heals |
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Term
| the interaction of t cells with MHC molecules |
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Definition
1) a fragment of foreign protein inside the cell associates with an MHC molecule and is transported to the cell surface
2) the combination of MHC molecule and antigen is recognized by a T cell, alerting it to the infection |
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Term
| the central role of helper t cells in humoral and cell-mediated immune responses |
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Definition
1) after a dendritic cell engulfs and degrades a bacterium, it displays bacterial antigen framents complexed with a class II MHC molecule on the cell surface. A specific helper T cell binds to the displayed complex via its TCR with the aid of CD4. This interaction promotes secretion of cytokines by the dendritic cell
2) proliferation of the t cell, stimulate by cytokines from both the dendritic cell and the T cell itself, gives rise to a clone of activated helper T cells, all with receptors for the same MHC-antigen complex
3) the cells in this clone secrete other cytokines that help activate B cells and cytotoxic T cells |
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Term
| the killing action of cytotoxic T cells |
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Definition
1) a specific cytotoxic T cells binds to a class 1 MHC-antigen complex on a target cell via its TCR with the aid of CD8. This interaction along with cytokines from helper T cells, leads to the activation of the cytotoxic cell
2) the activated T cell releases perforin molecules, which form pores in the target cell membrane, and proteolytic enzynmes which enter the target cell by endocytosis
3) the granzynes initiate apoptosis within the target cell,m leading to fragmentation of the nucleus, release of small apoptotic bodies and eventual cell death. The released cytotoxic T cell can attack other target cells |
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Term
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Definition
1) after a macrophage engulfs and degrades a bacterium, it displays a peptide antigen complexed with a classes II MHC-molecule. A helper T cell that recognizes the displayed complex is activated with the aid of cytokines secreted from the macrophage, forming a clone of activated helper T cells.
2) a b cell that has taken up and degraded the same bacterium displays class II MHC-peptide antigen complexes. an activated helper T cell bearing receptors specific for the displayed antigen binds to the B cell. This interaction, with the aid of cytokines from the T cell, activates the B cell.
3)The activated B cell proliferates and differentiates into memory B cells and antibody-secreting plasma cells. The secreted antibodies are specific for the same bacterial antigen that initiated the response |
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