FIG. 8.

i.n. challenge of immunized cotton rats with wild-type MV. Groups of four to five cotton rats were immunized i.n. with 2 to 7 × 10⁹ CFU of CVD 908-htrA and CVD 1208 alone or carrying plasmids pGA3-mH and pMSIN-H; i.m. with 100 μl (1 μg/μl) of plasmids pGA3-mH and pMSIN-H and i.n. with PBS (control) as described in Fig. 6. One month after the third dose, animals were challenged i.n. with wild-type MV (10⁷ PFU in 100 μl). Pulmonary virus was measured in lung homogenates 4 days after challenge. The results are reported as the mean log₁₀ TCID₅₀/g of lung tissue ± the SE. The data represent the average for four to five animals. Significant differences between groups, when present, are indicated.