T cell(redirected from T-lymphocyte A)
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See also: B lymphocyte.
A specialised myocyte found in clusters in the sinus node, which is intermediate in size, structure, and organisation between P cells and normal atrial myocytes, and connect swith either of these cells; perinodal T cells surround the sinus tract and are thought to “bundle” impulses leaving the sinus node and to filter premature ectopic atrial impulses.
A thymus-derived white cell responsible for cell-mediated immunity and immunoregulation which is the most complex cell of the immune system, given:
(1) The diversity of T-cell types, including T cells with activator, cytotoxic, delayed hypersensitivity and suppressor activities;
(2) The wide range of cytokines, growth factors and immune modulators produced by activated T cells;
(3) The complexity of T-cell interaction with exogenous and endogenous antigens (e.g., mediation of delayed hypersensitivity, graft-versus-host disease);
(4) The complexity of T-cell maturation in the thymus.
50 to 70% of circulating WBCs are granulocytes (neutrophils); the rest are lymphocytes, of which T cells (defined as having “pan T cell” markers), CD2 and CD7 and other T-cell markers (e.g., CD1, CD3, and CD5) comprise 70 to 85%; B cells comprise 15 to 30%.
See also: B lymphocyte
Synonym(s): T cell.
T cellOne of the two broad categories of LYMPHOCYTE, the other being the B cell group. Subsets of T cells with different functions include cytotoxic T cells (CD8+ T cells) which destroy tumour cells and cells infected with viruses; helper T cells (CD4+ T cells) which assist the immune response, and are a target of HIV infection; REGULATORY T CELLS, formerly called suppressor T cells, which are essential for the maintenance of immunological tolerance; and natural Killer T cells (NKT cells).
Patient discussion about T cell
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Q. what is difference between normal cell and a cell infected with cancer?
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