Comparison of the effects of interleukin‐1α, interleukin‐lβ and interferon‐γ‐inducing factor on the production of interferon‐γ by natural killer

Publisher Website
Google Scholar
Abstract
Interferon‐γ inducing factor (IGIF) is a recently identified cytokine which stimulates the production of interferon‐γ (IFN‐γ) by T cells and enhances natural killer (NK) cell cytolytic activity. Protein fold recognition, structure prediction and comparative modeling have revealed that IGIF is a member of the interleukin (IL)‐1 cytokine family and has prompted the designation IL‐1γ. Here we report functional similarities between members of the IL‐1 family by comparing the effects of IL‐1α, IL‐1β and IGIF on NK cell production of IFN‐γ. All three IL‐1 types enhanced NK cell production of IFN‐γ when induced by IL‐2 or IL‐12, although at high concentrations (>10 ng/ml), IGIF was five‐ to tenfold more potent than IL‐1α or IL‐1β. This effect correlated with enhanced levels of mRNA for IFN‐γ when NK cells were stimulated with IGIF plus IL‐12. In contrast to IL‐12 and IL‐2, the ability of IGIF to stimulate NK cell production of IFN‐γ was not increased by IL‐1α or IL‐1β. The ability of IGIF to enhance IFN‐γ production was independent of the type I and type II IL‐1 receptors or the IL‐1R accessory protein. Together, these results identify IGIF as a potent stimulator of NK cell production of IFN‐γ and demonstrate that the effect of IGIF on NK cell production of IFN‐γ is similar to that of IL‐1α and IL‐1β but distinct from that of IL‐12.