Membrane-associated complement factor H on lymphoblastoid cell lines Raji expresses a co-factor activity for the factor I-mediated cleavage of C3b.
Evidence of factor H was found on the surface of Raji cells derived from two different lines; a 150,000 MW species identical to 150,000 MW plasma factor H was detected. Rosette experiments performed at physiological ionic strength using EAC3b or EC3b were negative. In contrast, Raji cells expressed a co-factor activity in the factor I-mediated cleavage of fluid-phase C3b. This activity was cell number dependent and was inhibited by anti-factor H but not by anti-CR1. Raji cells did not secrete factor H in the extracellular medium.
Demares
M J
MJ
Laboratoire de Recherche DIFEMA, UFR de Médecine, Saint-Etienne de Rouvray, France.
D001402:B-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D003179:Complement C3b; D003180:Complement C3b Inactivator Proteins / Q000502:physiology*; D017242:Complement Factor H; D005340:Fibrinogen / Q000502:physiology*; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*
C493495:CFH protein, human; D003180:Complement C3b Inactivator Proteins; D008565:Membrane Proteins; D003179:Complement C3b; D017242:Complement Factor H; D005340:Fibrinogen