FIG. 3.

Comparison of anti-parasite activities of memory CD8⁺ T cells induced by sporozoites or by recombinant vaccinia virus. SYVPSAEQI-specific memory CD8⁺ T cells were generated from mice that received 1.0 × 10⁶ naïve transgenic CD8⁺ T cells, and the mice were subsequently immunized with either 0.5 × 10⁶ irradiated (γ source; 20 krad) sporozoites or 5 × 10⁶ PFU rec-VV. Twenty-five days after immunization, purified memory CD8⁺ T cells obtained from spleens were adoptively transferred into naïve mice. Recipient and control mice were challenged 2 days later with 3 × 10⁴ viable sporozoites. Thirty-four hours after challenge, the livers of infected mice were excised, and parasite load was measured using real-time PCR. The bar graph represents the number of P. yoelii 18S rRNA copies per liver. These data are representative of two independent experiments using four mice per group.