COMPARATIVE HUMORAL RESPONSES TO HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1-P24(GAG) LINEAR B-CELL EPITOPES AMONG INDIVIDUALS SHOWING ATYPICAL WESTERN IMMUNOBLOTTING REACTIONS AND IMPLICATIONS FOR DIAGNOSIS

Serum specimens from 25 individuals with an isolated human immunodefic iency virus type 1 (HIV-1) core antigen reactivity in a Western immuno blot test were examined for their reactivities with HIV-1 virions, con trol cellular antigens, HIV-1-Bru p24gag recombinant protein (p24gag), and a panel of 22 p24gag-derived peptides. The results were as follow s: (i) serum specimens from eight HIV-1-uninfected subjects did bind t o virions but failed to bind to p24gag; (ii) sera from 13 HIV-1-uninfe cted subjects and from one HIV-2-infected patient reacted with HIV-1 v irions and p24gag but failed to bind to any of the peptides expressing major p249gag epitopes; and (iii) 3 serum specimens obtained from one neonate carrying anti-HIV-1 maternal antibody and from two HIV-1-infe cted subjects who had seroconverted during the study reacted with HIV- 1 virions, p249gag, and one or more peptides containing the major p24g ag epitopes. Our data suggest that the combination of p24gag and appro priate peptides could be useful for resolution when atypical Western i mmunoblot results are encountered.