FIG. 9.

Effect of the route of immunization on pulmonary CD8⁺ T-cell responses and protection against intranasal vaccinia virus challenge. Mice primed by the i.m. inoculation of DNA-gp120 or pulmonary inoculation of PEI-DNA-gp120 received homologous boosting immunizations with the same immunogen using the same route of administration. Twelve weeks following the boost immunization, mice were challenged by the intranasal instillation of a lethal dose (2 × 10⁶ PFU) of vaccinia virus. (A) p18-specific CD8⁺ T cells in the lungs and MLN of immunized mice 12 weeks following the boost immunization. Pulmonary immunity data were generated from five to six mice/group, and data are represented as percentages of tetramer-binding CD8⁺ T cells ± SE. MLN data were generated from three independent pools of three mice. Statistically significant differences between groups were analyzed using Student's t test (***, P < 0.001). (B) Weight loss following intranasal vaccinia virus challenge (five to eight mice per group); cross symbols indicate mortality. (C) Vaccinia virus titers in the lungs and ovaries of immunized mice were determined 5 days following challenge (five to nine mice per group). Differences between groups were analyzed with a one-way ANOVA test (***, P < 0.001).