CD4+ lymphocyte function with early human immunodeficiency virus infection.

The pathogenesis of cellular immune deficiency following human immunodeficiency virus (HIV) infection could result from quantitative and/or qualitative dysfunction of the CD4+ lymphocyte population. To better characterize the T-cell response to soluble antigen with HIV infection, we have isolated peripheral blood lymphocytes and purified populations of CD4+ lymphocytes from healthy HIV antibody-positive subjects, patients with acquired immunodeficiency syndrome (AIDS)-related complex (ARC), and healthy HIV antibody-negative controls. T-lymphocyte function was determined by proliferative response to lectin (phytohemagglutinin), phorbol 12-myristate 13-acetate (PMA), calcium ionophore, purified recombinant HIV envelope gp120, tetanus toxoid antigen, and tetanus toxoid antigen in the presence of recombinant gp120 or purified recombinant soluble CD4. PBLs and CD4+ lymphocytes from asymptomatic HIV-infected subjects responded equally well to lectin, PMA, and/or calcium ionophore and to tetanus toxoid as cells from uninfected control subjects. The cells that proliferated in response to a soluble antigenic stimulus did not respond to gp120. Cells from subjects with ARC had a selective antigen recognition defect independent of the number of CD4+ lymphocytes. Recombinant gp120 inhibited CD4+ lymphocyte proliferation to antigenic stimulus by 30-40%. Recombinant soluble CD4, a proposed therapeutic for HIV, had no effect on T-cell response to antigen. A selective antigen recognition response was not compromised early in HIV infection but was compromised in subjects with ARC. Inhibition of proliferation to tetanus toxoid by gp120 suggests that HIV may affect major histocompatibility complex II restricted antigen recognition independent of CD4+ cell loss.