Figure 6
Serum neutralizing antibody titers measured following vaccination and BRSV challenge of colostrum-deprived calves. Sera was harvested from calves pre-vaccination and weekly following intranasal vaccination and diluted two-fold for determination of virus neutralization titers. Treatment groups of calves included: unvaccinated, uninfected controls (n = 5); intranasal (i.n.) allantoic fluid vaccinated (mock vaccine control) and BRSV challenged (n = 6); i.n. wtNDV-vaccinated and BRSV challenged (n = 5); i.n. rNDV-BRSV Fopt vaccinated and BRSV challenged (n = 6). Data are presented as mean titer per group. Note that the only group of calves whose mean titer was 1:4 or higher was the group receiving i.n. vaccination with rNDV-BRSV Fopt and this was sustained from boost to the end point of each of the 3 experiments.
