Function and regulation of memory CD4 T cells.
The development of peripheral naive CD4 T cells is dependent on the success of positive selection of immature T cells in the thymus. Only thymocytes that express a T cell receptor (TCR) capable of recognizing self-MHC with low affinity are selected for survival and differentiation into mature naive T cells. Although the TCR of naive T cells has to maintain self-tolerance, it also propagates naive CD4 T cell proliferation on recognition of appropriate foreign peptide associated with MHC class II on antigen-presenting cells (APCs). Naive CD4 T cells that successfully engage foreign peptide undergo further differentiation that leads to the maturation of a select few into the memory T cell pool. Although the requirements that lead to memory T cell development are currently not known, functional changes have been described that are thought to be associated with the greater efficiency with which memory T cells respond to antigen. This article will discuss differences associated with signaling through the TCR of naive and memory CD4 T cells and describe unique control mechanisms imposed on memory CD4 T cells that are likely to have ari sen to counterbalance the altered TCR signaling.
Metz
D P
DP
Yale Medical School, Section of Immunobiology, New Haven, CT 06520, USA.
Bottomly
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D000069594:Abatacept; D000818:Animals; D000938:Antigen-Presenting Cells / Q000502:physiology; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000502:physiology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D060908:CTLA-4 Antigen; D002454:Cell Differentiation; D018796:Immunoconjugates; D007156:Immunologic Memory; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D015398:Signal Transduction; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology
D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; D018796:Immunoconjugates; D011948:Receptors, Antigen, T-Cell; D000069594:Abatacept