Study on the synthesis of complement components by human renal mesangial cells in culture. Assessment of the effect of cytokines.

Renal mesangial cell (MC) cultures are easily established and widely used. MC produce some complement (C) regulatory proteins. We studied whether MC synthesize C components (C3, C5, C8). MC cultures were established from normal portions of cortices of nephrectomies for renal cancer. After growing to near-confluence in RPMI/17% FBS and resting for 24 h in RPMI/0.5% FBS, MC were stimulated up to 72 h with IL-1 beta or IL-6 (10, 100, 1000 U/ml). Neither C5 nor C8 were detected by ELISA. While C3 was present in supernatant under basal conditions (15.5-107.6 ng/10(6) cells/24h) in different MC lines. IL-1 beta up-regulated the synthesis by 2.4-4.5 folds, whereas IL-6 did not show any effect. C3 synthetic rate was 1.76 ng/h/10(6) cells under IL-1 stimulation versus basal rate of 0.37 ng/h/10(6) cells. MC production of C3, especially induced by IL-1 may have pathogenetic relevance in glomerulonephritis.