EXPRESSION OF THE COMPLEMENT CLASSICAL PATHWAY BY HUMAN GLIOMA IN CULTURE - A MODEL FOR COMPLEMENT EXPRESSION BY NERVE-CELLS

In this paper we demonstrate the synthesis of the components of the cl assical complement pathway, namely C1q, C1r, C1s, C1-Inh, C2, C4, and C5, by human glioma cell lines (U118MG, T193, and T98G). All these com ponents were structurally, antigenically, and functionally similar to their serum counterparts as determined by biosynthetic labeling experi ments, Western blot analysis, and hemolytic assays. Northern blot anal ysis of mRNA demonstrated that, for each of these components, their sp ecific mRNA had the same size as the equivalent mRNA from hepatic tiss ue. We could not detect the synthesis of C4bp by these cell lines, and the secretion of C1q was only detected after stimulation by interfero n-gamma. All these syntheses were up-regulated by interferon-gamma and tumor necrosis factor. Interleukin-1beta only increased C2 expression and reproducibly down-regulated C5 secretion when used at high doses. Glioma cell lines appear to be an efficient and convenient model for the analysis of complement expression in human astrocytic cells.