Expression and release of interleukin-1 by human glioblastoma cells in vitro and in vivo

The present study demonstrates interleukin-1 (IL-1) production by human glioblastorna cells bothin vitro andin vivo. The presence of IL-1α and IL-1β transcripts was analyzed in 4 cell lines. IL-1α mRNA was expressed constitutively in one cell line whereas constitutive IL-1β mRNA could not be detected in any of the cell lines. IL-1α transcripts could be induced with phorbol myristate acetate (PMA) or PMA plus lipopolysaccharide (LPS) in 2 of 4 cell Unes and IL-1β mRNA in 2 of 4 cell lines. Culture fluid from these cell lines was tested for the presence of IL-1 using a specific radioimmuno-assay for either IL-1α or IL-1β. In agreement with the results on RNA, one of 4 cell lines was found to constitutively produce IL-1α but not IL-1β. After treatment with PMA and LPS, IL-1α was detected in the culture fluid from two other lines and IL-1β in the medium from three lines. That the IL-1 produced by these cell lines was biologically active was confirmed in a two step thymocyte proliferation assay. IL-1 like activity was detected in all samples that were positive in the radio-immuno-assay.