title: CD3+ WT31- peripheral T lymphocytes lack T44 (CD28), a surface molecule involved in activation of T cells bearing the alpha/beta heterodimer.
abstract: We have applied two-color fluorescence cytofluorometric techniques to the analysis of the distribution of T44 and CD3 antigens in peripheral blood human lymphocytes. While most CD3+ cells co-expressed T44 antigen, a small distinct subset was CD3+ T44- (2-10% of CD3+ cells). This cell subset also did not react with the WT31 monoclonal antibody (mAb), specific for an alpha/beta framework determinant of the T cell receptor (TCR). Lack of T44 antigen expression was also observed in purified CD3+ WT31- polyclonal populations that had been cultured in medium containing interleukin 2 (IL2) and as well as greater than 30 clones expressing the CD3+4-8-WT31- surface phenotype. Immunoprecipitation experiments confirmed that expression of T44 molecules was confined to CD3+ WT31+ peripheral blood T cells. While conventional CD3+ WT31+ cells produced IL2 in response to mAb directed to CD2, CD3 or T44 surface molecules, CD3+ WT31- cells did not respond to anti-T44 mAb but released IL2 following stimulation with anti-CD2 or anti-CD3 mAb. Therefore, assuming that anti-T44 mimicks the effect of a still undefined natural ligand our data suggest that T cells expressing the gamma-gene surface product may be signalled by stimuli which differ, at least in part, from those acting on CD3+ WT31+ T lymphocytes.
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology*; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis*; D005434:Flow Cytometry / Q000379:methods; D006128:Growth; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation; D010641:Phenotype; D011233:Precipitin Tests; D011487:Protein Conformation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D012967:Sodium Dodecyl Sulfate; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D000939:Epitopes; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D012967:Sodium Dodecyl Sulfate