Cloning and characterization of a new isoform of mouse interleukin-18.
Interleukin-18 (IL-18) is a novel proinflammatory cytokine with potent interferon (IFN)-lambda inducing activity that plays an important biological role in the enhancement of the activity of natural killer cells and cytotoxic T lymphocytes. In this study, we have identified a novel short form of IL-18 in mouse, named IL-18s. IL-18s might be an alternative splicing variant of IL-18 and its cDNA contains a 57 bp in-frame deletion. Like IL-18, IL-18s is also widely expressed in mouse tissues. It was suggested that IL-18s might have a caspase-1-dependent mechanism for maturation and secretion similar to that of IL-18: when transfected in COS-7 cells, pro-IL-18s (22 kDa) could be detected, and the mature IL-18s (16 kDa) could also be detected when combined with caspase-1. We observed that recombinant mouse IL-18s did not show any IL-18-like function, and IL-18s could enhance the ability of IL-18 to increase IFN-lambda production by approximately 40% in mouse splenocytes. This effect was observed primarily at relative low concentrations of IL-18, suggesting that IL-18s might regulate the activity of IL-18 in the physiological conditions.
Yang
Yong-Jie
YJ
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences; Graduate School of the Chinese Academy of Sciences, Shanghai 200031 China.
Wang
Zhao-Yuan
ZY
Chen
Song-Hua
SH
Ge
Xi-Rui
XR
D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D007371:Interferon-gamma / Q000378:metabolism; D020382:Interleukin-18 / Q000737:chemistry* / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism*
D020382:Interleukin-18; D020033:Protein Isoforms; D007371:Interferon-gamma