FIG. 3.

In vitro proliferation of splenocytes from DNA-vaccinated BALB/c and C3H mice after stimulation with TLA. Splenocytes from individual mice were harvested 2 months after the third DNA dose. Following 72 h of stimulation with TLA, [³H]thymidine was added for 18 h. The incorporated radioactivity was then measured. Control splenocytes were from mice receiving the plasmid DNA without insert. For comparative purposes, splenocytes from BALB/c and C3H mice chronically infected with strain 76K (25 cysts per os) were included in the experiment. ∗, P < 0.05; ∗∗, P < 0.01.