Activation of the alternative complement pathway and production of factor H by skeletal myotubes.
Skeletal muscle myotubes from neonatal rats were used to study the interaction of skeletal muscle with complement. Serum from guinea pig, rabbit, and human, in the absence of muscle-specific antibody, caused creatine phosphokinase release, which required activation of the terminal complement cascade. Cleavage of serum C3 and Factor B in the presence of myotubes was dependent on Mg2+, but not Ca2+, and C3 cleavage occurred only in the presence of Factor B. Rat myotubes caused significant consumption of C8 and C9 in rat serum, which also required Mg2+, but not Ca2+. All of these findings are typical of a tissue capable of activating the alternative pathway. In addition, the C2 myotube cell line was shown to produce Factor H, an inhibitory protein of the alternative pathway, as demonstrated by Factor H mRNA expression and immunoprecipitation of the protein.
Lang
T J
TJ
Department of Pathology, University of Maryland School of Medicine, Baltimore.
Shin
M L
ML
D000818:Animals; D003176:Complement C3 / Q000378:metabolism; D017242:Complement Factor H / Q000096:biosynthesis* / Q000235:genetics; D015938:Complement Membrane Attack Complex / Q000378:metabolism; D003170:Complement Pathway, Alternative; D006168:Guinea Pigs; D006801:Humans; D009132:Muscles / Q000276:immunology* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D051381:Rats
C493495:CFH protein, human; D003176:Complement C3; D015938:Complement Membrane Attack Complex; D012333:RNA, Messenger; D017242:Complement Factor H