Detection of distinct patterns of anti-tat antibodies in HIV-infected individuals with or without Kaposi's sarcoma

Patterns of antibody response to recombinant transactivator protein (HIV-I rat) in serum samples from HIV-l-negative persons (n = 60), HIV-l-infected asymptomatic persons (n = 20), HIV-1-infected people with Kaposi's sarcoma (n = 25) and of people with Kaposi's sarcoma without HIV-1 infection have b een analyzed. None of the healthy people had anti-tar IgG in their serum. A ll asymptomatic patients with HIV-1 infection were anti-tat IgG-positive. E pitope mapping revealed that these sera have anti-tar IgG to all the functi onal domains of tat protein. Four of the 25 HIV-1-infected patients with Ka posi's sarcoma were anti-tar IgG-positive; however, epitope analysis reveal ed that IgG to functional domains of rat protein, in particular to TAR-bind ing site, were absent. All patients with Kaposi's sarcoma without HIV-1 inf ection were anti-tat IgG-negative. Presence or absence of anti-tat IgG, and prevalence of different antibody profiles in different groups of patients suggest the pathophysiologic role of tat protein. Thus, a passive immunizat ion with anti-tat IgG could be a useful strategy to influence the pathophys iologic state of the disease.