NationMaster - Encyclopedia: Immunogen

An antigen is any molecule that is recognized by antibodies. Usually, an antigen is a protein or a polysaccharide, but it can be any type of molecule, even small molecules if coupled to a large carrier (haptens). Wikipedia does not yet have an article with this exact name. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ... A hapten is a small molecule which can elicit an immune response only when attached to a large carrier such as a protein; the carrier may be one which also does not elicit an immune response by itself. ...

Antigens are presented by a cell to its environment via a histocompatibility molecule. Depending on the antigen presented and the histocompatibility molecule used, several types of immune cells can leap into action. A macromolecule is a molecule composed of a very large number of atoms. ... This article needs cleanup. ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates containing many genes with important immune system roles. ... White Blood Cells is also the name of a White Stripes album. ...

Exogenous antigens are antigens that have entered the body, e.g., by inhalation, ingestion, or injection. These antigens are taken up by endocytosis or phagocytosis into the antigen-presenting cells (APCs), and degraded into fragments. The fragments are then presented on the surface of APCs by class II histocompatibility molecules to T helper cells (CD4⁺). Those that are specific for them, get activated, so they start to secrete cytokines. The cytokines then activate cytotoxic lymphocytes T (CTL), antibodies secreting lymphocytes B, macrophages and other cells. Endocytosis is a process whereby cells absorb material (molecules or other cells) outside their cell membranes. ... In phagocytosis (literally, cell eating), large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a food vacuole. ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates containing many genes with important immune system roles. ... Cytokines are small protein molecules that are the core of communication between immune system cells, and even between immune system cells and cells belonging to other tissue types. ... Macrophages (Greek: big eaters) are cells found in tissues that are responsible for phagocytosis of pathogens, dead cells and cellular debris. ...

Endogenous antigens are antigens that have been generated within the cell, as a result of normal cell metabolism, or because of viral or intracellular bacterial infection. The fragments are then presented on the cell surface in the complex with class I histocompatibility molecules. If cytotoxic CD8⁺ T cells recognize them, they begin to secrete different toxins that cause the lysis or apoptosis of the infected cell. In order to keep the cytotoxic cells from killing cells just for presenting normal proteins, they run through a test cycle (negative control in the thymus) just after their production. Only those CTL that do not react to normal body protein fragments are allowed to enter the bloodstream. Santorio Santorio (1561-1636) in his steelyard balance, from Ars de statica medecina, first published 1614 Metabolism (from μεταβολισμος(metavallo), the Greek word for change), in the most general sense, is the ingestion and breakdown of complex compounds, coupled with the liberation of energy, and the consequent generation of waste... Infection is also the title of an episode of the television series Babylon 5; see Infection (Babylon 5). ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates containing many genes with important immune system roles. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... For a list of biologically injurious substances, including toxins and other materials, as well as their effects, see poison. ... Lysis (Greek lusis from luein = to separate) is the reduction of symptoms of a disease the dissolving of cells osmotic lysis chemical lysis viral lysis a dialogue of Plato about friendship (philia) This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same... In biology, apoptosis (from the Greek words apo = from and ptosis = falling, pronounced ap-a-tow-sis[1]) is one of the main types of programmed cell death (PCD). ... Thymus, see Thyme. ...

Categories: Immune system | Immunology A request has been made on Wikipedia for this article to be deleted in accordance with the deletion policy. ... Humoral immunity is mediated by secreted antibodies, produced in cells of the B lymphocyte lineage (B cell). ... Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of macrophages and NK-cells, the production of antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. ... In mammals including humans, the lymphatic vessels (or lymphatics) are a network of thin tubes that branch, like blood vessels, into tissues throughout the body. ... White Blood Cells is also the name of a White Stripes album. ... B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response). ... Schematic of antibody binding to an antigen An antibody is a protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ... The major histocompatibility complex (MHC) is a large genomic region or gene family found in most vertebrates containing many genes with important immune system roles. ... A lymphocyte is a type of white blood cell involved in the human bodys immune system. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... A cytotoxic (or TC) T cell is a T cell (a type of white blood cell) which has on its surface antigen receptors that can bind to fragments of antigens displayed by the Class I MHC molecules of virus infected somatic cells and tumor cells. ... A helper (or TH) T cell is a T cell (a type of white blood cell) which has on its surface antigen receptors that can bind to fragments of antigens displayed by the Class II MHC molecules found on professional antigen-presenting cells (APCs). ... B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response). ... Plasma cells are B lymphocytes that secrete immunoglobulins (antibodies). ... Memory B cells are B cells that although activated by the immune system, they are stored inside the circulatory system for later use, for long periods of time, possibly a whole lifetime. ...