FIG. 2.

LRT (A) and URT (B) prophylactic efficacies of murine anti-RSV-A MAbs and polyclonal sera. Groups of six or seven mice received a single dose each of 10⁴ anti-RSV-A ELISA titer equivalents of antibody 24 h before challenge with 10⁵ TCID₅₀ of RSV-A by i.n. instillation. Control mice received murine anti-BB polyclonal serum (at an anti-BB ELISA titer equivalent of 10⁴). Mice were sacrificed 5 days later, at which point the lungs were removed and 10% lung homogenates were prepared. Nasal tracts were rinsed by forcibly injecting 1.5 ml of virus transport medium through the nasopharyngeal cavity and recovering exudate from the nares. Virus titers were determined as described in Materials and Methods.