Interleukin-1 beta induces complement component C3 and IL-6 production at the basolateral and apical membranes in a human intestinal epithelial cell line

In previous studies, stimulation of cultured enterocytes with IL-1 beta res ulted in production of IL-6 and complement component C3. The cellular mecha nisms of these responses in the enterocyte are not fully understood. We tes ted the hypothesis that IL-1 beta-induced C3 and IL-6 production is differe ntially regulated at the apical and basolateral membranes of the enterocyte . Caco-2 cells (a transformed human colonic carcinoma cell line) were grown in a 2-chamber system to full differentiation. The cells were treated with IL-1 beta either at the apical or basolateral membrane, and C3 and IL-6 mR NA levels and release of C3 and IL-6 into the apical and basal chambers wer e determined. The release of C3 was greatest into the basal chamber regardl ess of whether the cells were stimulated at the apical or basolateral membr ane. In contrast, the production of IL-6 was greatest at the cell membrane that was stimulated with IL-1 beta. Stimulation of the Caco-2 cells with IL -1 beta resulted in increased mRNA levels for C3 and IL-6 with no major dif ferences noted when the cells were treated at the apical or basolateral mem brane. The results suggest that enterocyte production and release of at lea st some acute phase proteins and cytokines are differentially regulated at the apical and basolateral membrane of the enterocyte after stimulation wit h IL-1 beta.