Autoimmune renal injury in C3- and C4-deficient mice: a histological and functional study.
BACKGROUND
Complement deficiency predisposes to autoimmune renal disease. Since complement deficient mice are increasingly used to study the immunopathogenesis of renal disease we have determined whether mice deficient in C3 or C4 are susceptible to spontaneous immune-mediated renal injury.


METHODS
C3-deficient, C4-deficient and complement-sufficient, wild-type mice were maintained in standard conditions for 1 year at which stage renal function, renal histology, circulating antibody and autoantibody levels were assessed.


RESULTS
No significant decline in renal function was demonstrated in the complement-deficient mice. However, there was histological evidence of glomerular injury in both the C3- and C4-deficient mice, but of insufficient severity to alter function. Serum IgG2a concentration was significantly lower in C3- and C4-deficient mice. In contrast C3-deficient mice had higher concentrations of serum IgG2b. There was a tendency for mice from all groups, including the complement-sufficient mice, to develop autoantibodies. C4-deficient mice had higher titres of anti-dsDNA IgG but otherwise deficient mice had similar autoantibody titres to controls.


CONCLUSIONS
We conclude that C4-deficient mice demonstrate a small increase in autoantibody production at 1 year of age compared to C3-deficient and wild-type mice. Furthermore, although complement-deficient mice exhibit glomerular changes, they are of minor functional significance, and are unlikely to affect the study of experimentally induced renal disease in these mice.
Kouki
P
P
Department of Nephrology and Transplantation, Guy's Hospital, King's College London, London, UK.
Marsh
J E
JE
Sacks
S H
SH
Sheerin
N S
NS
D000818:Animals; D001323:Autoantibodies / Q000096:biosynthesis / Q000097:blood; D001327:Autoimmune Diseases / Q000097:blood / Q000473:pathology / Q000503:physiopathology*; D003176:Complement C3 / Q000172:deficiency*; D003181:Complement C4 / Q000172:deficiency*; D005260:Female; D005629:Frozen Sections / Q000379:methods; D005921:Glomerulonephritis / Q000097:blood / Q000473:pathology / Q000503:physiopathology; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000097:blood; D007150:Immunohistochemistry / Q000379:methods; D007678:Kidney Glomerulus / Q000276:immunology / Q000473:pathology* / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D008817:Mice, Mutant Strains
D001323:Autoantibodies; D003176:Complement C3; D003181:Complement C4; D007074:Immunoglobulin G; D007075:Immunoglobulin M