The C5a receptor is expressed by human renal proximal tubular epithelial cells

The C5a receptor is expressed by a variety of cell types. These studies dem onstrate by immunohistochemistry that the receptor is present on the surfac e of proximal and distal tubular epithelial cells from normal kidney. In ad dition, the receptor was detected on transitional epithelial cells of the u reter and bladder. Primary proximal tubular cultures and a proximal tubular cell line both also expressed the C5a receptor, as demonstrated by immunof luorescence and by FACS analysis. The presence of mRNA encoding the recepto r was confirmed by reverse transcriptase-polymerase chain reaction analysis . As opposed to its effect on glomerular mesangial cells, the receptor did not mediate a proliferative response by the proximal tubular cells. C5a als o did not enhance the synthesis/secretion of transforming growth factor-bet a 1, monocyte chemoattractant protein-1, platelet-derived growth factor-AB or tumour necrosis factor-alpha by cultured proximal tubular cells. Therefo re, although the C5a receptor clearly is expressed by proximal tubular cell s, clarification of its functional relevance on this cell type awaits furth er studies.