Normal peripheral proliferative and cytokine responses are observed in BIO 5192-treated mice 5 days following cessation of short-term treatment. Spleen cells from 5 mice per group were harvested 5 days after the last of 22 treatments were administered (day 44 after priming at the peak of the posttreatment disease exacerbation) 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 Δ CPM (media only backgrounds subtracted). Stimulation indices are shown above the relevant bars. Supernatants from the above culture in panel A were harvested at 48 and 72 hours and analyzed for IFN-γ secretion (B) and IL-2 secretion (C) in response to PLP139-151 by ELISA as described in “Materials and methods.”