Human T cell receptor gamma delta + T cells.
TCR gamma delta + T cells represent a minority of CD3+ T cells in many species including man. The molecular structure of the TCR gamma and delta loci in man is well understood. The gamma and delta loci contain V, D, J and C gene segments. These segments do not rearrange randomly but in a coordinated, ordered fashion during thymic development. Therefore, the structure of gamma and delta genes of early fetal TCR gamma delta + thymocytes differ drastically from those in postnatal TCR gamma delta + thymocytes. In contrast to postnatal TCR gamma delta + thymocytes, early fetal-TCR gamma delta + produce substantial levels of IL-4 and IL-5 and the possibility is discussed that the early fetal TCR gamma delta + cells are involved in development of TCR gamma delta + cells. In man, unlike in mouse, no preferential homing of early fetal TCR gamma delta + cells has been observed so far. Mature human peripheral TCR gamma delta + cells can recognize a great variety of cell surface antigens including 'classical' and 'non-classical' MHC antigens, immunoglobulins and other undefined antigens. In addition, TCR gamma delta + can recognize bacterial products. So far, no class of antigens has been defined that is preferentially recognized by TCR gamma delta + T cells and the function of these cells remains elusive.
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DNAX Research Institute, Human Immunology Department, Palo Alto, CA 94304-1104.
D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens; D002874:Chromosome Mapping; D016207:Cytokines / Q000096:biosynthesis; D000939:Epitopes; D015329:Gene Rearrangement, T-Lymphocyte; D006801:Humans; D011948:Receptors, Antigen, T-Cell / Q000032:analysis* / Q000235:genetics; D016692:Receptors, Antigen, T-Cell, gamma-delta; D013601:T-Lymphocytes / Q000276:immunology* / Q000502:physiology
D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D016827:CD8 Antigens; D016207:Cytokines; D000939:Epitopes; D011948:Receptors, Antigen, T-Cell; D016692:Receptors, Antigen, T-Cell, gamma-delta