HIV-1-infected patients with envelope-specific lymphoproliferation or long-term nonprogression lack antibodies suppressing glycoprotein 120 antigen presentation.

Abstract

Antibodies to the CD4-binding domain (CD4bd) of human immunodeficiency virus type 1 (HIV-1) glycoprotein 120 (gp120) inhibit gp120 antigen presentation to CD4 T cells. These findings imply that the presence of anti-CD4bd antibodies might contribute to the dearth of envelope-specific T helper responses observed in most HIV-1-positive patients. In the absence of these antibodies, however, anti-envelope T helper responses might be maintained. We used ELISA to evaluate the levels of anti-CD4bd antibodies in rare HIV-1-positive patients who exhibit envelope-specific lymphoproliferation. Subsequently, we examined the contribution of anti-CD4bd antibodies to disease progression by comparing anti-CD4bd antibody levels in 3 cohorts of HIV-1-positive patients with distinct rates of disease progression. Although most HIV-1-positive individuals produce anti-CD4bd antibodies, 77% of patients with envelope-specific lymphoproliferation have undetectable anti-CD4bd antibody levels. Moreover, comparison of the 3 HIV-1-positive cohorts revealed that individuals with long-term nonprogression have significantly lower anti-CD4bd antibody titers than do those with rapid or slow progression. Unlike immunoglobulin G (IgG) from rapid progressors, IgG from nonprogressors had no suppressive effects on glycoprotein (gp) 120-specific T cell proliferation. Low anti-CD4bd antibody levels are associated with the absence of disease progression. A number of HIV-1-positive individuals without these antibodies also appear to sustain gp120-specific T helper responses needed to help control the infection.