T cell requirements for generation of helper factor(s) in man: analysis of the subsets involved.
Lymphocyte mitogenic factor functions as a nonspecific helper molecule generated from antigen stimulation of T lymphocytes. As such, it induces proliferation of all major lymphocyte subclasses (T, B, and Null cells) and B cell immunoglobulin synthesis. In the present study, the specific T cell subset requirements for LMF production were determined in man. By utilizing the OKT4 monoclonal antibody directed at the human inducer T cell subset, T lymphocytes were separated into OKT4+ and OKT4- subpopulations. The antigen stimulated OKT4+ subset generated LMF in a fashion comparable to the unfractionated T cell population and was itself capable of directly inducing B cell proliferation and antibody production. In contrast, LMF could not be generated from the OKT4-T cell subset although this population accounted for 40% of the unfractionated T cell population. In addition, the OKT4- subset was unable to facilitate B cell differentiation in the presence of soluble antigen. These studies provide the first report of T cell subset restriction for generation of helper factors in man and further stress the importance of the OKT4+ inducer population in regulation of the human immune response.
D000941:Antigens; D001402:B-Lymphocytes / Q000166:cytology; D002455:Cell Division; D003593:Cytoplasm / Q000276:immunology; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis; D007376:Interleukin-2 / Q000378:metabolism / Q000494:pharmacology; D013601:T-Lymphocytes / Q000145:classification* / Q000166:cytology / Q000276:immunology
D000941:Antigens; D007136:Immunoglobulins; D007376:Interleukin-2