Murine CD4-CD8- thymocytes are stimulated by interleukin-2 to proliferate in vitro in chemically defined medium.
The ability of fetal and young adult CD4-CD8- thymocytes to proliferate in chemically defined (serum-free) medium in the presence and absence of IL-2 was examined. Dissociated thymocytes from day 15 and older fetal mice proliferated in vitro in the presence but not the absence of IL-2. The degree of proliferation was increased by including IL-1 with the IL-2. Inclusion of IL-1 in cultures of fetal thymocytes was associated with an increase in the number of IL-2 receptor positive cells, relative to cultures containing IL-2 alone. Although unfractionated thymocytes failed to proliferate in chemically defined medium, CD4-CD8- cells purified from thymic cell suspensions from young adult mice from several inbred strains proliferated to a limited extent in the absence of added cytokines. Proliferation was augmented 40-100 fold by inclusion of IL-2 in cultures. IL-1 stimulated some proliferation by young adult CD4-CD8- cells, but, unlike the effect of IL-1 and IL-2 on fetal thymocytes, combination of IL-1 with IL-2 did not have a notable additive effect on IL-2 induced proliferation. Proliferation stimulated by both IL-1 and IL-2 was completely abrogated by inclusion of anti-IL-2 receptor antibody in the cultures. Thymocytes from F1 progeny of inbred strains of mice proliferated to a greater extent in the absence of IL-2 than did thymocytes from either parent strain, although the response to IL-2 was not significantly different. The data demonstrate that both fetal and adult CD4-CD8- thymocytes area capable of proliferating in response to IL-2 in vitro, suggesting that, as is the case during antigen specific responses by mature T cells, IL-1 and IL-2 cooperate to stimulate T cell proliferation during development in vivo.
Department of Pathology and Oncology, University of Kansas Medical Center, Kansas City 66103.
G W
GW
Wood
J H
JH
Greenwood
D000818:Animals; D015704:CD4 Antigens / Q000032:analysis*; D016827:CD8 Antigens / Q000032:analysis*; D002478:Cells, Cultured; D003470:Culture Media; D005260:Female; D005333:Fetus / Q000276:immunology; D007375:Interleukin-1 / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008815:Mice, Inbred Strains; D011247:Pregnancy; D015375:Receptors, Interleukin-2 / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*
D015704:CD4 Antigens; D016827:CD8 Antigens; D003470:Culture Media; D007375:Interleukin-1; D007376:Interleukin-2; D015375:Receptors, Interleukin-2