Colitis model. In order to induce chronic colitis, ten-week old C57BL mice underwent three cycles of exposure to dextrane sulfate (DSS) in their drinking water for five days followed by 10-day intervals with regular tap water. By the end of the first cycle, mice were randomized into six treatment arms: vehicle control (PBS), total mouse IgG, and D8 given at increasing doses of 5µM, 25µM, 100µM and 200µM. Treatment was given by intraperitoneal (ip) injection in a 3X/week regimen. Body weight was documented twice a week. By the end of the last cycle, mice were sacrificed; the proximal portions of the colon were taken for immunohistochemical analysis and the distal portion for myeloperoxidase (MPO) activity assay (according to standard protocols) in order to assess the degree of the induced inflammation. The levels of inflammatory cytokines in the animals’ sera were detected by flow cytometry. Treatment with IgG or with D8 significantly attenuated body weight loss compared to vehicle-treated animals. Throughout the study, the highest body weight was observed in the 5µg D8 treatment arm (Figure 9A). MPO activity on day 34 was significantly reduced in the 5µg D8 treatment group compared to all other treatment arms including mIgG (Figure 9B). In addition, the level of inflammatory cytokines in the sera of the D8-treated animals was lower than that detected in control animals (Figure 9C). Immunohistochemical analysis of the proximal colon confirmed reduction in the level of damage to the colon tissue as well as reduction in the extent and degree of inflammation (Figure 9D). The extent of inflammatory infiltrate was evaluated by an expert pathologist.
