The relationship between collagen and C1q biosynthesis has been investigated in cultured human fibroblasts. This was done by measuring the effects of variation in cell density, inhibition of prolyl hydroxylase and complexing of C1q on synthesis and/or secretion of both proteins. It was found that synthesis and secretion of both proteins were not co-ordinate, and that therefore regulation of expression of both proteins is probably not linked. However complexing of C1q did result in marked stimulation in collagen synthesis, suggesting that the fibrosis which follows inflammation may result from binding of C1q to the immune complexes formed in the inflammatory process.
