Mice undergoing long-term treatment with BIO 5192 initiated at the peak of acute disease display enhanced proliferation and IFN-γ secretion in response to the priming PLP139-151 epitope. Spleen cells from 5 mice per group were harvested after 44 treatments (day 58 after priming) from the mice in Figure 2. (A) Viable spleen cells (5 × 10⁵/well) were cultured with indicated concentrations of PLP139-151 for 4 days and proliferation was assessed by incorporation of ³H-TdR. Results are expressed as ΔCPM (media only backgrounds subtracted). Stimulation indices are shown above the relevant bars. (B) Supernatants from the above culture in panel A were harvested at 48 and 72 hours and analyzed for IFN-γ secretion in response to PLP139-151 by ELISA as described in “Materials and methods.” (C) Five mice per treatment group were ear challenged with 10 μg PLP139-151 (left ear) and PLP178-191 (right ear) at day 57 after priming and increase in ear thickness as a measure of DTH was determined 24 hours thereafter. Values shown are mean net ear thickness (background swelling in challenged naive recipients subtracted) in units of 10^-4 inches ± SEM. ^*DTH responses significantly less than those of the vehicle-treated mice; P < .05.