Decay accelerating factor regulates complement activation on glomerular epithelial cells.
Epithelial cells of the glomerular capillary are the site of C5b-9 mediated injury in rat membranous nephropathy. We investigated the regulation of C activation by cultured glomerular epithelial cells (GEC). Rat and human GEC were more resistant to C injury by homologous C than heterologous C. In human GEC homologous C cytotoxicity was enhanced by antiserum to decay accelerating factor (DAF) indicating that homologous C activation was, at least in part, restricted by membrane DAF. Anti-DAF immunoprecipitated a 67-kDa protein from human glomeruli. In rat GEC, pronase and phosphatidylinositol-specific phospholipase C (which are known to inactivate human DAF) enhanced cytotoxicity by homologous C. Thus, DAF is present on human GEC in culture and in human kidney glomeruli, and a DAF-like protein is present on cultured rat GEC. These proteins regulate C activation in vitro and may play a role in controlling C activation on GEC in vivo.
Quigg
R J
RJ
Evans Memorial Department of Clinical Research, University Hospital, Boston, MA 02118.
Nicholson-Weller
A
A
Cybulsky
A V
AV
Badalamenti
J
J
Salant
D J
DJ
D000818:Animals; D018958:CD55 Antigens; D002478:Cells, Cultured; D003167:Complement Activation / Q000187:drug effects; D003185:Complement C8 / Q000276:immunology; D003186:Complement C9 / Q000276:immunology; D003169:Complement Inactivator Proteins / Q000502:physiology*; D003602:Cytotoxicity, Immunologic; D004492:Edetic Acid; D004848:Epithelium / Q000276:immunology; D006168:Guinea Pigs; D006801:Humans; D007678:Kidney Glomerulus / Q000276:immunology*; D008565:Membrane Proteins / Q000502:physiology*; D011817:Rabbits; D051381:Rats
D018958:CD55 Antigens; D003185:Complement C8; D003186:Complement C9; D003169:Complement Inactivator Proteins; D008565:Membrane Proteins; D004492:Edetic Acid