REACTIONS OF UGANDAN ANTISERA WITH PEPTIDES ENCODED BY V3 LOOP EPITOPES OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1

The specificities of antibodies reacting with peptides encoded by V3 l oop apical epitopes were determined for sera from 230 seropositive Uga ndans, including asymptomatic persons and AIDS patients, sampled betwe en 1986 and 1992. Most (71%) of the sera reacted with the peptide enco ded by HIV-MN, 59% reacted with a peptide containing a consensus seque nce for Ugandan variants of the HIV-1 global subtype A (referred to as the Uganda A consensus), and 59% reacted with a peptide containing a consensus sequence for Ugandan variants of the global subtype D (the U ganda D consensus); 19% of the sera also reacted with peptides encoded by the divergent Ugandan variant U31. There was no obvious correlatio n between the specificities of antibody binding and the V3 loop sequen ce of the corresponding virus isolate or provirus. Competitive inhibit ion and antibody adsorption experiments indicated that the MN peptide, the Uganda A consensus peptide, the Uganda D consensus peptide, and t he U31 peptide were recognized by different sets of antibodies. Eighte en percent of the sera from AIDS patients and 26% of the sera from asy mptomatic persons were monospecific for one of the MN, Uganda A, or Ug anda D peptides. Whereas all except one of the singly reactive AIDS se ra were specific for MN, 39% of the singly reactive asymptomatic sera were specific for MN, 39% for the Uganda A peptide, and 21% for the Ug anda D peptides. We conclude that analysis of the specificities of ant ibodies against the V3 loop epitopes in sera from asymptomatic persons could provide useful epidemiological data about the prevalence of vir al subtypes within a population.