Transforming growth factor beta (TGF beta) is produced by and influences the proliferative response of Xenopus laevis lymphocytes.
Both TGF beta 2 and 5 have been described in the South African clawed frog Xenopus laevis and have been cloned from the tadpole-derived fibroblast cell line, XTC. Because TGF beta has such a profound inhibitory effect on the mammalian immune system, this study was performed to determine whether TGF beta: (a) has any in vitro effects on the growth of Xenopus lymphoblasts, and (b) is produced by mitogen-activated Xenopus lymphocytes. Following stimulation with mitogen or alloantigen, T lymphocytes from Xenopus secrete a T-cell growth factor (TCGF) that is functionally homologous to mammalian interleukin-2 (IL-2). Both recombinant human TGF beta 1 and Xenopus TGF beta 5 inhibit TCGF-induced proliferation of Xenopus splenic blasts and this inhibition can be reversed with anti-pan TGF beta antiserum. The Xenopus mitogen-induced saturated ammonium sulfate precipitated TCGF-containing supernatant (SAS TCGF SN) also contains latent TGF beta as assayed on mink lung fibroblasts and Xenopus splenic blasts, and experiments utilizing anti-TGF beta antiserum showed that only TGF beta 5 is present in this supernatant.
Haynes
L
L
Department of Microbiology and Immunology, University of Rochester Medical Center, New York 14642.
Cohen
N
N
D000818:Animals; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D005260:Female; D007376:Interleukin-2 / Q000502:physiology; D008213:Lymphocyte Activation / Q000502:physiology*; D008907:Mink; D013154:Spleen / Q000166:cytology; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000502:physiology*; D014982:Xenopus laevis / Q000276:immunology*
D007376:Interleukin-2; D016212:Transforming Growth Factor beta