FIG. 5.

Neutralization of heterologous clade B primary HIV-1 isolates by macaque sera. Neutralization activities of sera collected 2 and 4 weeks following the DNA-plus-protein booster immunization against isolates heterologous to the vaccine primary HIV-1 isolates were determined as described in Materials and Methods. Dashed lines indicate 50, 70, and 90% inhibition of infection. The values represent specific neutralization, which is defined as the difference between the percent virus neutralization recorded with sera collected following vaccination and that recorded with sera collected prior to the initiation of vaccination. Data points indicate the mean percent specific neutralization from two independent experiments.