In vitro production of HIV-1 specific antibodies from at risk seronegative subjects

: We investigated a group of well characterized seronegative subjects "at risk" for HIV-1 infection including heterosexual partners of HIV-1 infected subjects and intravenous drug abusers. Pokeweed mitogen (PWM)-stimulated peripheral blood mononuclear cells (PBMCs) were studied for their ability to produce antibodies against HIV-1 structural proteins in vitro. Viral activity by means of HIV-1 isolation from PBMCs and presence of serum p24 antigen were also tested. In 7/42 cases (16.6%) HIV-1 immunoreactive specific antibodies were found, mostly directed against the envelope proteins (gp 120/160). Remarkably, none of these in vitro antibody producers yielded HIV-1 isolation in cell cultures or had detectable serum levels of p24 antigen.