FIG 4 .

Virus-neutralizing antibody activity (50% inhibitory concentration [IC₅₀] titers) against homologous HIV-1 clade B tier 1B strains (BaL.26) and heterologous clade B tier 1A strain MN.3 in sera from guinea pigs immunized with the indicated rNDVs. (A) Guinea pig sera obtained on days 21, 28, 56, 70, 90, and 160 were tested against BaL.26 pseudovirus by the TZM-bl assay. (B) Guinea pig sera obtained on days 21, 28, 56, 70, 90, and 160 were tested against MN.3 pseudovirus by the TZM-bl assay. Preimmune sera were used to establish values representing baseline-neutralizing activity in each individual guinea pig, and these values were subtracted from the values shown. The values for neutralizing antibody activity against each virus in sera obtained from guinea pigs immunized with parental rNDV control virus were <20 and are not shown in the graphs. The samples that did not neutralize the target virus (titers of <20) were given a value of 10 for plotting purposes; therefore, all results from samples registering an IC₅₀ titer of 10 are negative. Statistically significant differences in data from serological analysis of different immunized guinea pig groups were evaluated by one-way analysis of variance (ANOVA). P values of BaL.26-specific neutralizing antibody titer differences in comparisons of serum between different groups were <0.05. P values of MN.3-specific neutralizing antibody titer differences in comparisons of serum between different groups were <0.0001.