NITRIC-OXIDE PRODUCTION BY THE RAT INSULINOMA CELL-LINE, RINM5F, IS SPECIFIC FOR IL-1 - A SPECTROPHOTOMETRIC IL-1 BIOASSAY

Cytokines inhibit glucose-induced insulin secretion from pancreatic be ta-cells by stimulating the expression of nitric oxide synthase and th e increased production of nitric oxide (NO). We have found that the ra t insulinoma cell line, RINm5F, responds specifically and linearly to murine and human interleukin-1 beta (IL-1 beta) and IL-1 alpha in the range of 0.1 to 1 unit/ml to produce nitric oxide, Other cytokines, in cluding IL-2, IL-4, IL-6, IL-9, IL-11, IL-15, tumor necrosis factor-et c, interferon-gamma, and lipopolysaccharide fail to stimulate nitric o xide formation by RINm5F cells either alone or in combination. In addi tion, these cytokines do not significantly potentiate or attenuate the IL-1 response. This unprecedented specificity to IL-1 has been furthe r developed as a sensitive and specific assay for IL-1 bioactivity. Qu antitation by this new bioassay of human IL-1 beta and IL-1 released f rom activated murine peritoneal macrophages showed a close correlation with the quantitation of IL-1 by enzyme immunoassay (ELISA). This new bioassay, which is specific, nonradioactive and inexpensive, represen ts a significant improvement over current bioassays for IL-1. (C) 1996 Academic Press, Inc.