Nicotine and AR-R17779 fail to ameliorate collagen-induced arthritis (CIA). Male DBA/1 mice (6 to 8 weeks) were immunized for CIA on day 0 (100 μg chick type II collagen in complete Freund’s adjuvant containing 5 mg/ml of heat-killed Mycobacterium tuberculosis), followed by a booster injection on day 21 . Beginning on day 21, mice were treated intraperitoneally with nicotine (400 μg/kg), AR-R17779 (5 mg/kg) or vehicle (saline), twice daily for 7 days. (A) Cumulative incidence (percentage). (B) Change in paw thickness (calliper). (C) Clinical score (0 to 4 per paw; maximum score of 16 per mouse). Data are expressed as mean ± standard error of the mean; n = 8 mice per group.