HUMAN GLOMERULAR MESANGIAL CELLS EXPRESS CD16 AND MAY BE STIMULATED VIA THIS RECEPTOR

Human glomerular mesangial cells express CD16 and may be stimulated vi a this receptor. CD16, a low affinity receptor for IgG, was found on c ultured human glomerular mesangial cells (GMC) by Western blot analysi s, cell ELISA and in situ hybridization. To characterize the molecule in more detail, reverse polymerase chain reaction was performed and th e PCR products were analyzed. From sequence analysis and from hybridiz ation experiments with oligonucleotides specific for either the transm embrane form or the glycosylphosphatidylinositol anchored form it was found that GMC-CD16 was similar to NK-CD16. This indicates that GMC ex press the transmembrane form of CD16. Comparison between nonstimulated GMC and GMC stimulated by aggregated gammaglobulin revealed no qualit ative or quantitative difference in the expression of CD16. Incubation of GMC with aggregated gammaglobulin or with monoclonal antibodies to CD16 was followed by a time and dose dependent release of interleukin -6, suggesting that signals were transmitted by CD16. The occupancy of CD16 by immune complexes that may be deposited in various forms of gl omerulonephritis might contribute to the perpetuation of inflammatory processes in the kidney.