title: Complement C4 is protective for lupus disease independent of C3.
abstract: The role of complement C3 in mediating systemic lupus erythematosus (SLE) was examined using a double-knockout C3(null)C4(null) Fas (CD95)-deficient mouse model. Results from this study reveal significant lymphadenopathy, splenomegaly, elevated titers of anti-nuclear Abs and anti-dsDNA Abs, an increased number of anti-dsDNA-producing cells in ELISPOT assay, as well as severe glomerulonephritis in the double-deficient mice. Based on these clinical, serological, and histological parameters, we find that autoimmune disease in the double-knockout group is similar in severity to that in C4(null) lpr mice, but not to that in C3(null) lpr mice. The development of severe SLE in the absence of both classical and alternative complement pathways suggests that it is the absence of C4, and not the presence of C3, that is critical in SLE pathogenesis. Thus, complement C4 provides an important protective role against the development of SLE.
authors.affiliation: Center for Blood Research and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Shirit
authors.initials: S
authors.lastname: Einav
authors.forename: Olga O
authors.initials: OO
authors.lastname: Pozdnyakova
authors.forename: Minghe
authors.initials: M
authors.lastname: Ma
authors.forename: Michael C
authors.initials: MC
authors.lastname: Carroll
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000096:biosynthesis; D000921:Antibody-Producing Cells / Q000276:immunology / Q000378:metabolism; D000936:Antigen-Antibody Complex / Q000378:metabolism; D003176:Complement C3 / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D003181:Complement C4 / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D004247:DNA / Q000276:immunology; D005260:Female; D007668:Kidney / Q000276:immunology / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000235:genetics / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D019463:Mice, Inbred MRL lpr; D018345:Mice, Knockout; D009333:Neck; D009929:Organ Size / Q000276:immunology; D013154:Spleen / Q000276:immunology / Q000473:pathology
chemical_list: D000974:Antibodies, Antinuclear; D000936:Antigen-Antibody Complex; D003176:Complement C3; D003181:Complement C4; D004247:DNA