Reduction of oxidative state in inflamed knee by 1-11E/vIL10 fusion proteins. Antigen-induced arthritis was induced in female C57BL/6 mice by injecting mBSA into the knee of each animal 1 day before treatment (n = 3). On days 1 and 3 after mBSA rechallenge, animals were injected i.p. with 30 μg of 1-11E/vIL10 or C7/vIL10. As a control, PBS was injected. Level of inflammation and redox state were determined by monitoring the luminescence 15 minutes after i.p. administration of luminol, a redox-sensitive compound that glows when mixed with oxidizing agents present in the inflamed knee and thus correlates with degree of inflammation. (A) Representative luminescence images taken at days 1, 2, and 5 after injection of 1-11E/vIL-10, C7/vIL-10, and control nontreated mice are shown. (B) The reduction in oxidation level was faster in the 1-11E/vIL-10-treated animal than in C7/vIL-10 and nontreated mice, which correlated with reduction in swelling (C).