| receptors, antigen, T-cell | Molecules on the surface of T-lymphocytes that recognise and combine with antigens. The receptors are non-covalently associated with a complex of several polypeptides collectively called CD3 antigens (antigens, CD3). Recognition of foreign antigen and the major histocompatibility complex is accomplished by a single heterodimeric antigen-receptor structure, composed of either alpha-beta (receptors, antigen, T-cell, alpha-beta) or gamma-delta (receptors, antigen, T-cell, gamma-delta) chains. (12 Dec 1998) |
|---|---|
| receptors, antigen, T-cell, alpha-beta | T-cell receptors composed of CD3-associated alpha and beta polypeptide chains and expressed primarily in CD4+ or CD8+ T-cells. Unlike immunoglobulins, the alpha-beta T-cell receptors recognise antigens only when presented in association with major histocompatibility (MHC) molecules. (12 Dec 1998) |
| receptors, antigen, T-cell, gamma-delta | T-cell receptors composed of CD3-associated gamma and delta polypeptide chains and expressed primarily in CD4-/CD8- T-cells. The receptors appear to be preferentially located in epithelial sites and probably play a role in the recognition of bacterial antigens. The T-cell receptor gamma/delta chains are separate and not related to the gamma and delta chains which are subunits of CD3 (see antigens, CD3). (12 Dec 1998) |
| receptors, cell surface | Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behaviour of the target cell. Cell surface receptors, unlike enzymes, do not chemically alter their ligands. (12 Dec 1998) |
| marrow cell | Any cell of bone marrow, especially haemopoietic cell's. (05 Mar 2000) |
| parenchymal cell | See: parenchyma. (05 Mar 2000) |
| parenchymatous cell of corpus pineale | A cell of the pineal body with long processes ending in bulbous expansions. Pinealocytes receive a direct innervation from sympathetic neurons that form recognizable synapses. The club-shaped endings of pinealocyte processes terminate in perivascular spaces surrounding capillaries. Synonym: chief cell of corpus pineale, parenchymatous cell of corpus pineale. Origin: pineal + G. Kytos, cell (05 Mar 2000) |
| parent cell | A cell which, by division, gives rise to two or more daughter cell's. Synonym: brood cell, metrocyte, parent cell. (05 Mar 2000) |
| carotid body cell | <pathology> Cells derived from the neural crest, involved in sensing pH and oxygen tension of the blood. (18 Nov 1997) |
| Martinotti's cell | A small multipolar nerve cell with short branching dendrites scattered through various layers of the cerebral cortex; its axon ascends toward the surface of the cortex. (05 Mar 2000) |
| germ cell | Cell specialised to produce haploid gametes. The germ cell line is often formed very early in embryonic development. (18 Nov 1997) |
| germ cell tumour | A type of brain tumour. (12 Dec 1998) |
| germinal cell | A cell from which other cell's proliferate. (05 Mar 2000) |
| parietal cell | One of the cell's of the gastric glands; it lies upon the basement membrane, covered by the chief cell's, and secretes hydrochloric acid that reaches the lumen of the gland through fine intracellular and intercellular canals (canaliculi). Synonym: acid cell, oxyntic cell. (05 Mar 2000) |
| carrier cell | <cell biology> A cell that is capable of phagocytosis. The main mammalian phagocytes are neutrophils and macrophages. Origin: L. Phagedaena, Gr Phago, To eat. (18 Nov 1997) |