NEUTRALIZING ANTIBODIES AGAINST SEQUENTIAL AUTOLOGOUS HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 ISOLATES AFTER SEROCONVERSION

The emergence of human immunodeficiency virus type 1 (HIV-1) variants with different sensitivities to serum neutralization and biologic phen otype was studied for 2-5 years after primary HIV-1 infection in 5 sub jects. In 3 subjects, the initial virus isolate from seroconversion co uld be neutralized by autologous serum, but isolates obtained at two s ubsequent times exhibited reduced sensitivity to serum neutralization, decreased replication in primary macrophages, and increased ability t o induce syncytia. Two of these 3 subjects progressed to AIDS and died . Sequential virus isolates from the other 2 subjects showed variabili ty in sensitivity to serum neutralization or biologic features. These patients remained relatively stable in clinical status. Thus, viruses isolated at seroconversion appear to be either non-syncytium-inducing, strong macrophage-tropic, serum neutralization-sensitive phenotypes w ith stable clinical status or to have escaped neutralization by autolo gous sera over time, have reduced macrophage tropism and increased syn cytia formation, and be associated with disease progression.