Neutralizing parameters for selected sera against low doses of the heterologous HIV-189.6 primary isolate.

†Number of fluorescent cells/dose of infectious virus.¶Number of fluorescent cells (point where plot crosses vertical axis).§Gradient of plot with serum from immunized macaque divided by gradient of plot with control serum expressed as a percentage.#Dose of infectious virus (interval between points where plots for sera from immunized and control macaques cross horizontal axis).Significant difference with controls:***p**p*p