ELISA reactivity of mouse sera against HIV-1 gp120. Five mice each were immunized with recombinant RVs (SBN, SBN-89.6, or SBN-NL4-3), and, 3 months after the initial infection, three mice of each group were boosted with recombinant HIV-1 gp120 and gp41 (SBN*, SBN-89.6*, or SBN-NL4-3*). Each data point on the graph indicates the average of mice from each group in three independent experiments. One mouse of the SBN-89.6 group did not react to the boost injection and was not included in the graph. The error bars indicate the standard deviations.