Frequent coexpression of cytolytic activity and lymphokine production among human T lymphocytes. Production of B cell growth factor and interleukin 2 by T8+ and T4+ cytolytic clones.
These studies were designed to determine the degree of overlapping between cytolytic function and lymphokine production among peripheral blood human T lymphocytes. T8+ and T4+ cells were obtained by sorting purified T cells using the fluorescence-activated cell sorter (FACS) and cloned at 0.25 cells/well in a microculture system that allows clonal growth of every T cell. 49/49 T8+ clones but only 5/102 T4+ clones displayed cytolytic activity, as assessed by a lectin-dependent assay. Cytolytic clones were further analyzed for their ability to release interleukin 2 (IL2) and B cell growth factor(s) (BCGF) upon 24 h stimulation with phytohemagglutinin. Fifteen percent and 18% of T8+ cytolytic clones were producing IL2 and BCGF, respectively; in addition 3 out of 5 T4+ cytolytic clones released both lymphokines. Although the majority of cytolytic clones producing IL2 were also producing BCGF, 5 clones released either BCGF or IL2. The present studies indicate that the coexpression of cytolytic and helper/inducer functions is relatively common among peripheral blood T lymphocytes, irrespective of their T8+ or T4+ phenotype.
D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D006133:Growth Substances / Q000096:biosynthesis*; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis*; D015847:Interleukin-4; D008222:Lymphokines / Q000096:biosynthesis*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D006133:Growth Substances; D007376:Interleukin-2; D008222:Lymphokines; D015847:Interleukin-4