Functional analysis of human T cell subsets defined by monoclonal antibodies. III. Regulation of helper factor production by T cell subsets.
In the present report we extended our previous studies demonstrating that obligatory T-T interactions are important in regulating human immune responses in vitro. Functionally distinct human T cell subsets were isolated by complement-mediated lysis using the monoclonal antibodies OKT4 and OKT8. Evidence was obtained that during allogeneic interactions, OKT4+, but not OKT8+, responder T cells are required to generate helper factor(s) capable of polyclonally activating human B cells independent of additional T cell help. Importantly, the alloantigen-induced helper factor(s) production and/or release was found to be suppressed by addition of graded numbers of radiosensitive OKT8+ cells. On the other hand, no evidence was obtained that supernatant derived from alloactivated OKT8+ cells could counterbalance the helper activity generated in the presence of supernatant from alloactivated OKT4+ cells. Furthermore, OKT8+ cells, known to suppress PWM-driven B cell differentiation in the presence of OKT4+ cells, do not suppress B cell differentiation induced by preformed helper factor even in the presence of OKT4+ cells. These data further underscore the importance of functional T-T interactions in immunoregulation in vitro and support the idea that the target of suppression of B cell differentiation, induced either by alloantigen-triggered helper factor or PWM, are OKT4+ cells and not B cells themselves.
D000906:Antibodies / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology; D002454:Cell Differentiation; D002999:Clone Cells / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D007959:Lymphocyte Culture Test, Mixed; D011043:Pokeweed Mitogens / Q000494:pharmacology; D013601:T-Lymphocytes / Q000145:classification* / Q000378:metabolism
D000906:Antibodies; D011043:Pokeweed Mitogens