Background |
Autoantibodies to type II collagen play a primary role in the collagen induced arthritis (CIA) model. However, autoantibodies are not always capable of inducing arthritis due to the inability to activate a complement, the first critical step in the activation of inflammatory cascades. In CIA susceptible DBA mice, complement fixable IgG2a and IgG2b subtype autoantibody levels, as well as their epitope specificity, are pertinent in the induction of arthritis. In order to adequately study the pathological roles of antibodies to type II collagen, it is important to determine individual IgG subtype autoantibody levels to mouse type II collagen as well as the heterologous type II collagen used for immunization. On the other hand, C57BL/6 mice, a popular strain for developing transgenic mice, produce IgG2c antibodies instead of IgG2a antibodies due to its MHC class I haplotype (H-2b). Moreover, these mice can only develop CIA when immunized with chick type II collagen. Therefore, serum IgG2c autoantibody levels against mouse type II collagen and chick type II collagen should be evaluated when using C57BL/6 mice for the CIA model. |