Neutralization of primary HIV-1 isolated from individuals residing in Rio de Janeiro. HEC/FIOCRUZ AIDS Clinical Research Group.

Abstract

Efforts have been made to control HIV-1 infection through the induction or passive transfer of HIV-1 neutralizing antibodies. Results are presented from an analysis of the susceptibility to neutralizing antibodies of 27 primary HIV-1 isolates obtained from infected individuals living in Rio de Janeiro. Autologous and heterologous neutralization susceptibility to neutralization by control NAb and the capacity to neutralize a reference HIV-1 isolate were determined. Traditional neutralization assays using a mixture of phytohemagglutinin (PHA) activated mononuclear cells obtained from HIV-1 seronegative blood donors were conducted. Study results indicate a rather high percentage of isolates susceptible to autologous neutralization (11/16 isolates 68.7%) when positive autologous neutralization was defined as the capacity to neutralize more than 50% of the virus in comparison to viral detection in control wells in the absence of antisera. This percentage is probably higher than what would be detected in a greater sample. When 80% activity reduction is defined as positive neutralization 43.7% of the isolates tested were neutralized by their autologous antisera. The great majority of the autologous plasma neutralized the autologous HIV-1 isolate at very low titers. 15.4% of the isolates appear to be highly susceptible to the autologous neutralizing antibodies as detected by the capacity of autologous NAb to neutralize higher viral concentrations. 6.7% of the primary isolates were completely neutralized by the autologous NAb.