FIGURE 4.

The T_reg cells induced by Salmonella-CFA/I vaccination suppress effector T cells, and their in vivo inactivation results in enhanced clinical disease. A, CD25⁻CD4⁺ and CD25⁺CD4⁺ T cells from spleens, MLN, and HNLN were cell sorted from mice orally immunized with H696 for 2 wk. T_eff (1 × 10⁵) cells with feeder (1 × 10⁵) cells were cultured with CFA/I fimbriae and with or without T_reg (5 × 10⁴) cells for 4 days. During the last 18 h of culture, cells were pulsed with [³H]TdR. Proliferation in the absence of T_reg cells was set at zero inhibition. Depicted is the percent inhibition upon coculture with splenic, MLN, or HNLN T_reg cells. One of three experiments is depicted. B, One week before PLP_139–151 challenge, mice (five per group) orally immunized with H696 were treated in vivo with anti-CD25 mAb, rat IgG, or PBS on days −5 and −2 before challenge. Inactivation of T_reg cells provoked greater EAE than the PBS-treated group. Normal rat IgG-treated mice vaccinated with H696 showed minimal EAE. *, p < 0.001 for anti-CD25-treated group vs H696-vaccinated or H696-vaccinated plus normal rat IgG-treated mice.