Figure 6.

Paw swelling response in delayed-type hypersensitivity (DTH) arthritis following treatment with tumor necrosis factor alpha (TNFα)-blocking biologics or dexamethasone. (a, b) Rat anti-mouse TNFα mAb (anti-TNFα) was administered from the time of immunization (prophylactic), and control groups received rat IgG1 (rIgG1). Mean ± standard error of the mean (SEM) is shown (n = 9 to 10 per group). Area under the curve (AUC) was calculated from days 0 to 10 after arthritis induction. Both prophylactic treatment and treatment at onset with anti-TNFα resulted in a significant reduction in the footpad swelling response. (c, d) Etanercept, a soluble TNF receptor fused to the Fc part of human IgG, was administered therapeutically (from day 1), and control groups received humanized anti-trinitrophenol (anti-TNP hzIgG1). A vehicle (saline) control group was also included. Mean ± SEM is shown (n = 9 to 10 per group). AUC was calculated from days 0 to 10 after arthritis induction. Therapeutic treatment with etanercept resulted in a significant reduction in footpad swelling when administered at 50 mg/kg. Treatment with 25 and 50 mg/kg both resulted in a significant reduction in the footpad swelling response when compared with the saline control group (indicated by ##). (e, f) Dexamethasone, a glucocorticoid, was administered daily from time of disease onset, and control groups received no treatment. Mean ± SEM is shown (n = 9 to 10 per group). AUC was calculated from days 0 to 10 after arthritis induction. Daily treatment with dexamethasone from time of disease onset significantly reduced the paw swelling response when compared with the untreated control group. The levels of significance are defined as follows: *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, ^##P ≤ 0.01.