IL-1 production as a regulator of G-CSF and IL-6 production in CSF-producing cell lines

We previously demonstrated that colony stimulating factor (CSF)-producing cell lines co-produce interleukin-1 (IL-1) and IL-6 in addition to CSFs. In the present study, we examined the role of IL-1 production in three human tumour cell lines producing granulocyte (G)-CSF, IL-1 and IL-6. Addition of anti-human IL-1 alpha antiserum to the culture caused a 90-62% reduction of G-CSF and a 85-44% reduction of IL-6 production, respectively, as evaluated by enzyme immunoassay in all three cell lines. The decrease of G-CSF and IL-6 production by the anti-IL-1 alpha antiserum was also confirmed at the level of mRNA expression. The anti-IL-1 alpha antiserum did not affect the growth of these cell lines. Excess recombinant IL-1 alpha exogenously added to the culture enhanced G-CSF and IL-6 production in all three cell lines. However, IL-1 alpha had little effect on the growth of these three cell lines. Neither anti-IL-6 nor anti-G-CSF antibodies affected the production of the other cytokines. These results indicate that IL-1 alpha regulates G-CSF and IL-6 production in these tumour cell lines, and suggest that the IL-1 production plays an important role in CSF-producing tumours.