Interleukin 2 induces antigen-reactive T cell lines to secrete BCGF-I.
Antigen-activated T lymphocytes produce within 24 h of stimulation a factor that is indistinguishable biochemically and functionally from the B cell co-stimulating growth factor, BCGF-I, originally identified in induced EL4 supernatants: Supernatants from antigen-stimulated T cell lines are not directly mitogenic for resting B cells, but synergize in an H-2-unrestricted manner with anti-Ig activated B cells to produce polyclonal proliferation but not antibody-forming-cell development; biochemical studies reveal the B cell co-stimulating factor present in antigen-stimulated T cell line supernatants is identical by phenyl Sepharose chromatography and isoelectric focusing (IEF) to EL4 supernatant BCGF-I. We thus conclude that normal T cells produce BCGF-I in response to antigenic stimulation. Analysis of the mechanism of BCGF-I production by antigen-stimulated T cells showed that optimum amounts of BCGF-I were obtained as quickly as 24 h post-stimulation, and that the factor producing cells in the T cell line investigated bore the Lyt-1+2- phenotype. As few as 10(4) T cells produced sufficient BCGF-I to support the proliferation of 5 X 10(4) purified anti-Ig activated B cells. Finally, the activation of normal T cell lines to produce BCGF-I required either antigen presented in the context of syngeneic antigen-presenting cells (APC) or interleukin 2 (IL-2).
D000818:Animals; D002460:Cell Line; D002845:Chromatography; D006133:Growth Substances / Q000378:metabolism*; D007376:Interleukin-2 / Q000502:physiology*; D015847:Interleukin-4; D007525:Isoelectric Focusing; D051379:Mice; D008962:Models, Theoretical; D013601:T-Lymphocytes / Q000378:metabolism*
D006133:Growth Substances; D007376:Interleukin-2; D015847:Interleukin-4