Autoantibodies to the collagenous region of C1q occur in three strains of lupus-prone mice.
We have developed an ELISA to measure murine autoantibodies to the collagenous region (CLR) of C1q, using the whole human C1q molecule as the solid-phase ligand, in the presence of 1 M NaCl. The assay was validated by testing positive sera from 20 mice using purified mouse C1q, and from 10 mice using purified human C1q-CLR, as the solid-phase ligands. There were highly significant correlations between results obtained with human C1q (whole molecule) and: (i) mouse C1q (rsp = 0.73, P less than 0.001), and (ii) human Clq-CLR alone (rsp = 0.86, P = 0.001). Antibodies to Clq were measured in 53 MRL/lpr, 17 BXSB and 25 NZB/W lupus-prone mice. Median (range) anti-C1q (CLR) antibody levels in MRL/lpr, BXSB, and NZB/W autoimmune mice aged 3 months were 22 (16-66), 21 (17-39) and 19 (15-27) EU, respectively. The median anti-Clq antibody level in MRL/lpr mice aged 5 months was 76 (35-142) EU, significantly higher than that at 3 months (U = 558, P less than 0.0005). Median anti-C1q antibody level in NZB/W mice at 8 months was 37 (13-74) EU and in BXSB mice at 11 months was 62 (31-231) EU, significantly higher than corresponding values at 3 months (U = 326, and U = 4, P less than 0.001, respectively). This is the first demonstration of anti-C1q (CLR) antibodies in NZB/W and BXSB mice. The pathologic significance and the potential utility of these antibodies for monitoring disease in lupus-prone mice are under evaluation.
Hogarth
M B
MB
Rheumatology Unit, RPMS, London, UK.
Norsworthy
P J
PJ
Allen
P J
PJ
Trinder
P K
PK
Loos
M
M
Morley
B J
BJ
Walport
M J
MJ
Davies
K A
KA
D000375:Aging / Q000276:immunology; D000818:Animals; D000974:Antibodies, Antinuclear / Q000737:chemistry; D001323:Autoantibodies / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry / Q000276:immunology*; D015922:Complement C1q / Q000276:immunology*; D003176:Complement C3 / Q000378:metabolism; D004247:DNA / Q000276:immunology; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000209:etiology / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008814:Mice, Inbred NZB; D008817:Mice, Mutant Strains; D009994:Osmolar Concentration; D011485:Protein Binding / Q000276:immunology; D013045:Species Specificity
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D003176:Complement C3; D015922:Complement C1q; D003094:Collagen; D004247:DNA