Second signal activity of IL-12 on the proliferation and IL-2R expression of T helper cell-1 clone.
In these experiments, effects of IL-12 on the proliferation and IL-2R expression of Th1 and Th2 clones were studied. Although neither Th1 nor Th2 clones proliferated on an Ag stimulation with B cell APC, Th1 clones but not Th2 clones, exhibited IL-2-dependent proliferation in the presence of IL-12 in response to the Ag stimulation. The IL-2R alpha-chain was also shown to be induced on Th1 clones when they were stimulated with B cell APC in the presence of IL-12. Effects of IL-12 on these T cell functions were indicated to be exerted in concert with IL-2, although IL-12 did not enhance IL-2 production of Th1 clones. Cytokines produced by Th1 clones such as IFN-gamma and TNF-alpha were indicated not to be involved in induction of the IL-2R alpha-chain expression or proliferation. IL-12 also induced proliferation and IL-2R alpha-chain expression of Th1 clone stimulated with anti-CD3 in the absence of APC, indicating that IL-12 exerted the effect on Th1 cells directly and other costimulator signal from APC is not required for the function of IL-12. In contrast to IL-12, IL-1 induced proliferation and IL-2R alpha-chain expression of Th2 clones stimulated with Ag on B cell APC. The failure of IL-12 in the induction of IL-2R alpha-chain expression on Th2 clone seemed not to be caused by the IL-4 produced by the clone. These results suggest that IL-12 plays an important role in IL-2R alpha-chain expression and proliferation of Th1 clones, but not Th2 clones, as a second signal.
Yanagida
T
T
Department of Allergology, University of Tokyo, Japan.
Kato
T
T
Igarashi
O
O
Inoue
T
T
Nariuchi
H
H
D000818:Animals; D017252:CD3 Complex / Q000276:immunology; D002999:Clone Cells; D018664:Interleukin-12; D007376:Interleukin-2 / Q000096:biosynthesis / Q000494:pharmacology; D007378:Interleukins / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D006377:T-Lymphocytes, Helper-Inducer / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology
D017252:CD3 Complex; D007376:Interleukin-2; D007378:Interleukins; D015375:Receptors, Interleukin-2; D018664:Interleukin-12