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Definition
| 1. neutrophils 2. the cells of the mononuclear phagocyte system, including monocytes in the blood and macrophages derived from monocytes in the connective tissues 3. organ-specific phagocytes in the liver, spleen (Kupffer cells) , lymph nodes, lungs, brain ( microglia). |
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| movement toward chemical attractants which are a subclass of cytokines known as chemokines. Neutrophils are the first to arrive at the site of an infection; monocytes arrive later and can be transformed into macrophages. |
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| PGE2 release comes from the arachidonic acid pathway. This pathway (as it relates to fever), is mediated by the enzymes phospholipase A2 (PLA2), cyclooxygenase-2 (COX-2), and prostaglandin E2 synthase. |
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Definition
| An antigen or immunogen is a molecule that stimulates an immune response. Antigens are usually proteins or polysaccharides. This includes parts (coats, capsules, cell walls, flagella, fimbrae, and toxins) of bacteria, viruses, and other microorganisms. Lipids and nucleic acids are antigenic only when combined with proteins and polysaccharides. |
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Definition
| Haptens are low-molecular weight molecules which contain an antigenic determinant but which are not itself antigenic unless complexes with an immunogenic carrier. If they bind to protein and thus become antigenic determinant on the proteins. |
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Definition
| The three major types of lymphocyte are: T cells, B cells and natural killer (Nk) cells |
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| Functions of B lymphocytes |
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Definition
| B lymphocytes secrete antibodies that can bind to antigens in a specific fashion. |
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Definition
| Antibody proteins are also known as immunoglobulins. They are found in the gamma globulin class of plasma proteins. The five distinct bands of proteins that appear are albumin, alpha-1 globulin, alpha-2 globulin, beta globulin, and gamma globulin. These are identified by a technique called electrophoresis. There are five immunoglobulin subclasses: IgG, IgA, IgM, IgD, and IgE. Most of the antibodies in serum are in the IgG subclass, whereas most of the antibodies in external secretions (saliva and milk) are IgA, antibodies in the IgE subclass are involved in certain allergic reactions. |
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Definition
| 1. recognition-C1 2. activation-C4, C2, and C3 in that order 3. attack-C5 through C9 |
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Definition
| Molecular association of CD8+ T cells with MHC class I and CD4+ T cells with MHC class II Several different subsets of T cells have been described, each with a distinct function. |
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| are the "middlemen" of the adaptive immune system. Once activated, they divide rapidly and secrete small proteins called cytokines that regulate or "help" the immune response. Depending on the cytokine signals received, these cells differentiate into Th1, Th2, Th17 or other subsets, which secrete different cytokines. |
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| (Tc cells) destroy virally infected cells and tumor cells, and are also implicated in transplant rejection. These cells are also known as CD8+ T cells, since they express the CD8 glycoprotein at their surface. Through interaction with helper T cells, these cells can be transformed into suppressor T cells which prevent autoimmune diseases such as experimental autoimmune encephalomyelitis.(MHC 1) |
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| are a subset of antigen-specific T cells that persist long-term after an infection has resolved. They quickly expand to large numbers of effector T cells upon re-exposure to their cognate antigen, thus providing the immune system with "memory" against past infections. Memory T cells comprise two subtypes: central memory T cells (TCM cells) and effector memory T cells (TEM cells). Memory cells may be either CD4+ or CD8+. |
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Definition
| Treg cells), formerly known as suppressor T cells, are crucial for the maintenance of immunological tolerance. Their major role is to shut down T cell mediated immunity towards the end of an immune reaction and to suppress auto-reactive T cells that escaped the process of negative selection in the thymus. Two major classes of CD4+ regulatory T cells have been described, including: *The naturally occurring Treg cells and the adaptive Treg cells. Naturally occurring Treg cells (also known as CD4+CD25+FoxP3+ Treg cells) arise in the thymus, *The adaptive Treg cells (also known as Tr1 cells or Th3 cells) may originate during a normal immune response. |
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Term
| Natural Killer T cells (NKT cells) |
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Definition
| are a special kind of lymphocyte that bridges the adaptive immune system with the innate immune system. Unlike conventional T cells that recognize peptide antigen presented by major histocompatibility complex (MHC) molecules, NKT cells recognize glycolipid antigen presented by a molecule called CD1d. |
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Term
| Diseases caused by the immune system |
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Definition
| 1. Autoimmunity (example: Diabetes type I) Autoimmunity is the failure of an organism to recognize its own constituent parts (down to the sub-molecular levels) as "self", which results in an immune response against its own cells and tissues. 2. Complex diseases 3. Allergy a. Immediate hypersensitivity b. Delayed hypersensitivity |
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Definition
| a. Immediate hypersensitivity results when an allergen provokes the production of antibodies in the IgE class. These antibodies attach to tissue mast cells and stimulate the release of chemicals from the mast cells. b. Delayed hypersensitivity as in contact dermatitis, is a cell-mediated response of T lymphocytes. |
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