FIG 4.
rHRSV vaccine-induced HRSV-neutralizing antibodies before and after boost with HRSV challenge. (A) Cotton rats at 2 or 9 months of age were immunized with an rHRSV vaccine dose of 105 TCID50 or 104 TCID50, and the HRSV-neutralizing function of serum antibodies was analyzed at day 28, at the time when animals were challenged by infection with 3 × 105 TCID50 human wtHRSV. (B) The net increase in antibody levels was analyzed at 5 days after challenge. This graph shows data from one of two independent experiments on the rHRSV vaccine in young versus old cotton rats showing similar results. Values are expressed as log2 values. *, P < 0.05, as determined by ANOVA.