Treatment efficacy of 1-11E/vIL-10. A. AIA was induced in female C57BL/6-mice 1 day before treatment (n = 10-12). On days 1 and 3 after mBSA rechallenge, animals were injected i.p. with 30 μg of 1-11E/vIL10 or C7/vIL10 or PBS. Significant reduction in knee swelling in 1-11E/vIL-10 treated mice compared with mice treated with C7/vIL-10 or PBS controls was observed (P = 0.0048). (B) Safranin O staining of cartilage from nontreated AIA knee displayed weak staining. The cartilage from healthy control animals was smooth, with clear strong staining with safranin O. Cartilage from C7/vIL-10-treated mouse had weak safranin O staining compared with healthy controls. 1-11E/vIL-10-treated knees displayed histology similar to that of the healthy joints. (C) Serum cytokine levels in treated mice were obtained from mice treated with 1-11E/vIL10 or C7/vIL10 as well as from healthy control animals (HC) on day 3. Cytokines levels were measured with ELISA by using the 7-plex mouse Pro-Inflammatory Cytokine Kit. Except for IFN-γ, levels of pro-inflammatory cytokines were significantly lower in the 1-11E/vIL-10-treated animal (P = 0.0175) and similar to levels of healthy control animals (P > 0.05).