Protective efficacy of mucosal vaccination with Gcf.
Each group of immune mice was challenged with 1×106 PFU RSV A2 at 4 weeks after immunization and the levels of RSV replication in the lungs were determined by plaque assay at day 4 post challenge. Results are expressed as the mean ± SEM (n = 6). The limit of detection was 200 PFU/gram of lungs. N.D., not detected.