Experiment 3 (Solognot ewes): two groups of ewes were vaccinated by single injection with 10⁵ Mic1-3KO tachyzoites either s.c. or i.p. and were challenged per-os with 100 sporulated oocysts of the PRU strain at mid gestation. One group was infected but not vaccinated (control). (A) Mean ± S.D. rectal temperature of groups and (B) systemic IgG against T. gondii measured by ELISA after vaccination (means and S.D.). The solid line indicates a positive cut off point. (C) Mean ± S.D. rectal temperature following challenge.