Fig. 1.

Comparative analyses of Padi4^−/− and wild-type mouse models of experimental arthritis. Wild-type (n = 10) and Padi4^−/− (n = 7) mice were immunized with bovine type II collagen (CII) and boosted on day 21 (arrowheads). As control mice, Wild-type (n = 5), and Padi4^−/− mice (n = 5) were immunized with PBS. a Arthritis severity score. The severity of arthritis was graded according to the scale defined in Materials and Methods. The data are presented as the mean clinical score ± SEM. *P < 0.05 (U-test). b Incidence of arthritis. The percentage of affected animals in each group was determined on each day. The IgM isotype (c) and IgG isotype (d) of anti-CII antibodies in the wild-type and Padi4^−/− mice sera before and after injection, as determined by ELISA. * P < 0.05, **P < 0.01 (Student’s t-test)