FIG. 4.

Vaccination of BALB/c and DBA/2 mice with att and ts viruses. (A) Body weight in vaccinated BALB/c mice. Mice were vaccinated with Sw-att, Sw-ts, WF-att, WF-ts, or mock vaccinated. Body weight was monitored daily. (B) Lung viral titers in vaccinated BALB/c mice. After vaccination, two mice in each group were sacrificed at days 3 and 6 postvaccination. Lungs were homogenized in 1 ml of PBS, and viral titers were determined by plaque assay (mock, Sw-att, and Sw-ts) and EID₅₀ (WF-att and WF-ts). (C) Body weight in vaccinated DBA/2 mice. Mice were vaccinated with the Sw-att, WF-att, or mock vaccinated. Body weight was monitored daily. (D) Lung viral titers in vaccinated DBA/2 mice. After vaccination, two mice in each group were sacrificed at days 3 and 6 postvaccination. Lungs were homogenized in 1 ml of PBS, and viral titers were determined by plaque assay (mock and Sw-att) and EID₅₀ (WF-att).