CLINICAL, IMMUNOLOGICAL, AND VIROLOGICAL OBSERVATIONS RELATED TO HUMAN-IMMUNODEFICIENCY-VIRUS (HIV) TYPE-I INFECTION IN A VOLUNTEER IN AN HIV-1 VACCINE CLINICAL-TRIAL

A vaccine breakthrough occurred in a phase 1 clinical trial of a human immunodeficiency virus (HIV) type 1 candidate subunit vaccine. The va ccine antigen, gp120(SF2), is a fully glycosylated protein produced in mammalian cells from the HIVSF2 isolate. After 4 immunizations, the s ubject developed neutralizing antibodies and lymphoproliferative respo nses to the gp120 protein, About 18 weeks after the last immunization, the subject became HIV infected. During the acute phase of infection, there was high virus burden, a decline in CD4(+) T lymphocytes, incre ases in rgp120(SF2)-binding antibodies and HIVSF2- and HIVMN-neutraliz ing antibodies, and transient lymphoproliferative responses to HIV-1 e nvelope and core proteins. The nucleotide sequence of the V3 loop from 2 virus isolations displayed close similarity to the V3 sequence of t he vaccine antigen, Thus, the immunologic responses induced by the vac cine in this subject did not protect him from HIV-1 infection.