Lewis rats were subjected to active EAE induced by MBPp87–99/CFA and at the onset of disease were subjected to soluble peptide therapy with p87–99 or p68–86. Twenty-four hours later, cervical LNCs (a–d) and spleen (e–h) were subjected to flow cytometry analysis of IL-4 vs. IL-10 production by CD4⁺ T cells, gated by anti-CD4⁺ Ab as described in Methods. (a and e) Analysis of cells from a naive rat. (b and f) Analysis of cells from EAE rats treated with the soluble form of the determinant with which disease was induced (MBPp87–99). (c and g) Analysis of cells from EAE rats treated with the soluble form of the determinant of spread (MBPp68–86). (d and h) Analysis of cells from EAE rats treated with PBS.