title: Identification of a CD2- CD3+ T cell receptor-gamma+ peripheral blood lymphocyte subpopulation.
abstract: We have identified, in a healthy individual, a sub-population of human peripheral lymphocytes which surface express a CD3-TCR-gamma complex recognized by anti-Ti gamma A mAb, while being unreactive with a phycoerythrin-conjugated anti-CD2 antibody with T11/1 specificity. Further immunofluorescence analyses performed on uncultured cells indicated that such a putative CD2-CD3+ phenotype was restricted to a fraction of those T lymphocytes which carry a surface receptor of the "second family" (gamma/delta). The actual lack of CD2 expression was confirmed by a subsequent series of cloning experiments which showed that none of the three well characterized CD2 epitopic clusters, namely T11/1, T11/2, and T11/3, were detectable on the surface of the relevant cells. The cultured CD2-, CD3+/TCR gamma + lymphocytes were found to display, as well as their CD2+ counterparts, both non-MHC-restricted cytotoxic function and proliferative responses induced via the gamma receptor complex. In contrast, the proliferative capacity of the CD2-, CD3+/TCR-gamma + cells observed in a culture system designed for in vitro expansion of lymphocytes with undefined specificity was extremely limited. This may relate to an impaired interaction of the CD2- cloned lymphocytes with lymphocyte function-associated (LFA)3+ irradiated cells present in the feeder layer. Further characterization of such minor CD2- T lymphocytes subsets may help to better understand the biologic relevance of the CD2/LFA3 pathway of cell-cell interaction.
mesh_terms: D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis* / Q000276:immunology; D018801:CD2 Antigens; D002352:Carrier Proteins / Q000032:analysis / Q000276:immunology; D002999:Clone Cells / Q000145:classification / Q000276:immunology / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D005455:Fluorescent Antibody Technique; D006801:Humans; D051379:Mice; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000032:analysis* / Q000276:immunology; D011971:Receptors, Immunologic / Q000032:analysis / Q000276:immunology; D013601:T-Lymphocytes / Q000145:classification* / Q000276:immunology / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D002352:Carrier Proteins; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic