FIG 6 .

Protective efficacy of rNDVs against challenge with vaccinia virus-Gag (V V-Gag) and vaccinia virus-BaL Env. Mice in groups of 5 each were immunized with 105 PFU/ml of the indicated rNDV either alone or in a mixture of two rNDVs by the intranasal route on days 0 and 21. On day 63, mice were challenged by the intranasal route with either 107.2 TCID₅₀/ml of vaccinia virus-Gag (A) or 107.6 TCID50/ml of vaccinia virus-BaL Env (B). Five days after the challenge, the mice were sacrificed and lungs were collected. Lungs were homogenized, and viral titers, represented as PFU/ml, were determined by standard plaque assay on Vero cells. The data represent three similar experiments. P values of PFU/ml for comparisons between different groups were <0.0001.