Therapeutic effect of anti-TNF mAb, CTLA-4Ig, and anti-IL-6 mAb in GPI-induced arthritis. Glucose-6-phosphate isomerase (GPI)-immunized mice were treated with (a) anti-tumor necrosis factor (TNF)-α mAb; (b) anti-IFN-γ mAb or anti-IL-12 mAb; (c) cytotoxic T-lymphocyte antigen 4 immunoglobulin (CTLA-4Ig; on days 8 and 12); (d) CTLA-4Ig (on days 12 and 16); and (e) or anti-IL-6 mAb just after the onset of arthritis (on day 8, on days 8 and 12, or days 12 and 16; arrow). The mean clinical index (± standard error) was examined throughout the study. *P < 0.05, **P < 0.01, by Mann-Whitney's U test. n = 6 mice in each group. Hematoxylin and eosin staining at day 21 (×40) is also shown: (f) anti-TNF-α mAb, (g) control antibody, and (h) CTLA-4Ig (on days 8 and 12).