CD25+CD4+ regulatory T lymphocytes
Tuesday 30 August 2005
The immune system evolved to protect the host against the attack of foreign, potentially pathogenic, microorganisms. It does so by recognizing antigens expressed by those microorganisms and mounting an immune response against all cells expressing them, with the ultimate aim of their elimination.
Various mechanisms have been reported to control and regulate the immune system to prevent or minimize reactivity to self-antigens or an overexuberant response to a pathogen, both of which can result in damage to the host.
Deletion of autoreactive cells during T- and B-cell development allows the immune system to be tolerant of most self-antigens. Peripheral tolerance to self was suggested several years ago to result from the induction of anergy in peripheral self-reactive lymphocytes.
Avoidance of damage to the host is also achieved by active suppression mediated by regulatory T (T(reg)) cell populations.
Takahashi T, Sakaguchi S. Naturally arising CD25+CD4+ regulatory T cells in maintaining immunologic self-tolerance and preventing autoimmune disease. Curr Mol Med. 2003 Dec;3(8):693-706. PMID: 14682491
O’Garra A, Vieira P. Regulatory T cells and mechanisms of immune system control. Nat Med. 2004 Aug;10(8):801-5. PMID: 15286781