FIG. 4.

Proliferative responses of CD4⁺ Th cells from infected BL/6 and CBA mice to rTPx-1. CD4⁺ Th cells were isolated from mesenteric lymph nodes of 8.5-week-infected mice and incubated with the indicated antigens in the presence of APC as described in Materials and Methods. [³H]dThd incorporation was assessed by liquid scintillation spectroscopy. Also shown for comparison are responses to Sm-p40 and SEA. Background radioactivity from cultures in the absence of antigen is subtracted. The same patterns of stimulation were observed when cells from 8 -week-infected mice were used (not shown). The experiments were repeated at least three times with similar results.