Effect of prophylactic and therapeutic treatment with MAb 5261-muIg on CIA progression. (A-C) Prophylactic treatment. (D-F) Therapeutic treatment. (A and D) Arthritic indexes (AI). (B and E) Summary of the histological analysis. Statistical significance was evaluated using unpaired Student’s t-test (n = 10 mice/group); **P < 0.001; ****P < 0.0001. (C and F) Toluidine blue staining of the selected limbs. (C): AI at termination: 11 (control), 4 (MAb 5261-muIg). (F): AI at termination: 10 (control), 6 (MAb 5261-muIg), 4 (Etanercept). B – Bone, C – Cartilage, Syn – Synovial tissue. Thick arrows identify affected joints; yellow arrow – pannus; red arrow – infiltration of inflammatory cells. Results shown are representative of at least three independent experiments.