MeSH

Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.

Year introduced: 1990 (1973)

CD4-positive T cells that inhibit immunopathology or autoimmune disease in vivo. They inhibit the immune response by influencing the activity of other cell types. Regulatory T-cells include naturally occurring CD4+CD25+ cells, IL-10 secreting Tr1 cells, and Th3 cells.

Year introduced: 2006, 1985-1994

A critical subpopulation of regulatory T-lymphocytes involved in MHC Class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-LYMPHOCYTES, CYTOTOXIC) and CD8+ suppressor T-lymphocytes.

Year introduced: 1995

Subpopulation of CD4+ lymphocytes that cooperate with other lymphocytes (either T or B) to initiate a variety of immune functions. For example, helper-inducer T-cells cooperate with B-cells to produce antibodies to thymus-dependent antigens and with other subpopulations of T-cells to initiate a variety of cell-mediated immune functions.

Year introduced: 1993

A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.

Year introduced: 1995

Immunized T-lymphocytes which can directly destroy appropriate target cells. These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a graft-versus-host (GVH) reaction, or after immunization with an allograft, tumor cell or virally transformed or chemically modified target cell. The lytic phenomenon is sometimes referred to as cell-mediated lympholysis (CML). These CD8-positive cells are distinct from NATURAL KILLER CELLS and NATURAL KILLER T-CELLS. There are two effector phenotypes: TC1 and TC2.

Year introduced: 1990

T Lymphocytes with limited diversity of receptors (e.g., ALPHA E INTEGRINS) in the epidermis of the skin and the mucosal linings. They recognize common microbes via T-CELL RECEPTORS and PATHOGEN-ASSOCIATED MOLECULAR PATTERN MOLECULES and function as effector cells for INNATE IMMUNITY. Activation of intraepithelial lymphocytes is a marker for various gastrointestinal diseases (e.g., CELIAC DISEASE; HAIRY CELL LEUKEMIA; and ENTEROPATHY-ASSOCIATED T-CELL LYMPHOMA).

Year introduced: 2018

A subset of activated T cells generated in response to primary immune challenge or immunization upon re-challenge (see IMMUNOLOGIC MEMORY). Memory T cells feature many discrete properties indicative of various differentiation such as expression pattern of CCR7 RECEPTORS and can be divided into central memory and effector memory T cells.

Year introduced: 2022

RefSeq NM_015995

Date introduced: August 6, 2004