FIG. 5.

HEL-specific lymphocyte proliferation following i.n. immunization with HEL+EtxB or HEL+CtxB. Mice were immunized once i.n. with either 1 μg of HEL alone, 1 μg of HEL plus 30 μg of EtxB, 1 μg of HEL plus 30 μg of CtxB, or 1 μg HEL plus 1 μg of Ctx, as indicated. Controls received PBS. Seven days later, cell suspensions were isolated from CLN (A), MLN (B), ILN (C), and spleen (D). The cells were cultured in the presence or absence of 200 μg of HEL per ml for 72 h. Proliferation was measured by incorporation of [³H]thymidine during the final 15 h of culture, and data are mean counts per minute ± SEM from triplicate cultures. Dashed line, background proliferation from cultures without HEL. ∗, P < 0.05 compared to HEL+EtxB.