Figure 5
A single anti-CII antibody induces relapses. Induction of relapses in chronic mice (n = 6) injected with a single mAb, namely 9 mg of CIIC1 (open circles), M2139 (open squares) or UL1 (filled triangles). The incidence in the groups of mice injected with CIIC1 and M2139 was 100% and the incidence in the group of mice injected with UL1 was 83%. The selected chronic B10.Q (BALB/c×B10.Q)F2 mice had previously been immunized with 100 μg of rat CII in incomplete Freund's adjuvant (IFA) on day 0 and boosted on day 35 with 50 μg of rat CII in IFA. Mice that developed chronic arthritis (mice with severe arthritis for a minimum period of 120 days were considered to have chronic arthritis) were selected for the induction of relapses. Antibodies were injected on day 265 in these mice. Most of the mice had active arthritis before antibody injection (mean maximum score 8.1 ± 2.0). The basal level score from day 265 was subtracted from the observed arthritis score values in individual mice; 17% of these mice were relapsing on day 265. The basal levels of CII epitope-specific antibodies in sera just before injection of anti-CII antibodies are as follows: RCII, 95 μg/ml; C1, 15 AU; J1, 70 AU; and U1, 15 AU. Results are means ± SEM. AU, arbitrary units.