INTERLEUKIN-18 ACTIVATES NF-KAPPA-B IN MURINE T-HELPER TYPE-1 CELLS

Interleukin-18 (IL-18) activated T helper type 1 (Th1) cells, OVA#4, a nd induced production of interleukin-2 (IL-2) in costimulation with an ti-CD3 antibody. Upon stimulation with IL-18, I kappa B disappeared fr om cytoplasm and subsequently nuclear factor-kappa B (NF-kappa B) (p65 ) accumulated in the nucleus. Corresponding with that, DNA binding act ivity of NF-kappa B (p65 homodimer or p65/p50 heterodimer) was detecte d in the nucleus. In the transfection experiments, an IL-2 promoter-dr iven reporter construct showed the similar responsiveness against IL-1 8 to that of the intrinsic IL-2 gene, and a construct lacking kappa B site failed to respond to IL-18. These results suggest that IL-18 acti vates NF-kappa B and it is important for enhancement of IL-2 gene expr ession by Th1 cells stimulated with IL-18. (C) 1997 Academic Press.