Patterns of antibody reactivity to selected human immunodeficiency virus type 1 (HIV-1) gp160 epitopes infected individuals grouped according to CD4+ cell levels.

We examined sera from 160 HIV-infected individuals for antibodies reactive to HIV-1 gp160 epitopes defined by seven synthetic peptides. Seropositive individuals were placed into three groups based upon levels of circulating CD4+ cells. These groups consisted of individuals with (1) more than 400 CD4+ cells, (2) 200-400 CD4+ cells, and (3) fewer than 200 CD4+ cells/mm3. The percentage of sera containing antibodies reactive with two immunodominant gp160 epitopes (a.a. 304-321 and 600-611) was unchanged between groups, regardless of CD4 cell numbers. The percentage of sera containing antibodies reactive with weakly immunogenic gp160 epitopes, such as those defined by peptides 425-448 and 846-860, declined in the groups as CD4 values decreased. Our results suggest that the patterns of antibody reactivity to gp160 epitopes change as CD4 levels decline. A narrowing of the humoral immune response to epitopes on the envelope of HIV-1 appears to occur with disease progression.