| B lymphocyte | <haematology, immunology> An immunologically important lymphocyte, produced by the bone marrow, that is responsible for the production of immunoglobulins, it is the precursor of the plasma cell. The surface markers can be used to detect and differentiate chronic lymphocytic leukaemia from acute lymphocytic leukaemia. (13 Nov 1997) |
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| b-lymphocyte subsets | A classification of B-lymphocytes based on structurally or functionally different populations of cells. (12 Dec 1998) |
| gene rearrangement, b-lymphocyte | Ordered rearrangement of b-lymphocyte variable gene regions coding for the immunoglobulin chains, thereby contributing to antibody diversity. It occurs during the differentiation of the immature b-lymphocyte. (12 Dec 1998) |
| gene rearrangement, b-lymphocyte, heavy chain | Ordered rearrangement of b-lymphocyte variable gene regions thereby contributing to antibody diversity. It occurs during the first stage of differentiation of the immature b-lymphocyte. (12 Dec 1998) |
| gene rearrangement, b-lymphocyte, light chain | Ordered rearrangement of b-lymphocyte variable gene regions coding for the kappa or lambda light chains, thereby contributing to antibody diversity. It occurs during the second stage of differentiation of the immature b-lymphocyte. (12 Dec 1998) |
| gene rearrangement, t-lymphocyte | Ordered rearrangement of T-cell variable gene regions coding for the antigen receptors. (12 Dec 1998) |
| receptors, lymphocyte homing | Cell surface glycoproteins on lymphocytes and other leukocytes that mediate adhesion to specialised blood vessels called high endothelial venules. Several different classes of lymphocyte homing receptors have been identified, and they appear to target different surface molecules (addressins) on high endothelial venules in different tissues. The adhesion plays a crucial role in the trafficking of lymphocytes. (12 Dec 1998) |
| virgin lymphocyte | <haematology, immunology> A lymphocyte that has not and whose precursors have not, encountered the antigenic determinant for which it possesses receptors. (18 Nov 1997) |
| Rieder's lymphocyte | An abnormal form of lymphocyte that has a greatly indented (or lobed), slightly twisted nucleus; such cells are usually observed in certain examples of chronic lymphocytic leukaemia. (05 Mar 2000) |
| minor lymphocyte stimulatory antigens | Endogenous superantigens responsible for inducing strong proliferative responses in T-cells in mixed lymphocyte reactions (see mixed lymphocyte culture test). They are encoded by mouse mammary tumour viruses that have integrated into the germ line as DNA proviruses (minor lymphocyte stimulatory loci). (12 Dec 1998) |
| minor lymphocyte stimulatory loci | Genetic loci responsible for the encoding of minor lymphocyte stimulatory antigens. There are at least two unlinked loci (in the mouse) and they appear to be separate from the major histocompatibility complex and minor histocompatibility loci. The mouse mammary tumour virus (see mammary tumour viruses, mouse) has the ability to integrate into these loci. The antigens induce strong T-cell proliferative responses in mixed lymphocyte reactions. (12 Dec 1998) |
| mixed lymphocyte culture | <investigation> Test to determine whether a patients and donor's white blood cells interact adversely. Often used to determine whether a person would be a suitable bone marrow donor for a particular patient. (16 Dec 1997) |
| mixed lymphocyte culture test | Measure of histocompatibility at the hl-a locus. Peripheral blood lymphocytes from two individuals are mixed together in tissue culture for several days. Lymphocytes from incompatible individuals will stimulate each other to proliferate significantly (measured by tritiated thymidine uptake) whereas those from compatible individuals will not. In the one-way mlc test, the lymphocytes from one of the individuals are inactivated (usually by treatment with mitomycin c or radiation) thereby allowing only the untreated remaining population of cells to proliferate in response to foreign histocompatibility antigens. (12 Dec 1998) |
| mixed lymphocyte reaction | <haematology, immunology, investigation> Reaction of mitogenesis produced in T lymphocytes when allogeneic (i.e. Mixed) lymphocytes are brought together, provided they are mismatched in histocompatibility loci. Once used as a test for possible graft compatibility in human grafting. Now known that a negative reaction is a poor predictor of graft acceptance. (18 Nov 1997) |
| pre-B lymphocyte | An early B-lymphoid type cell that is recognised by immunofluorescence as a u-positive, L-chain-negative bone marrow cell. (05 Mar 2000) |