Lymphocyte proliferation assays may underestimate antigen responsiveness in human immunodeficiency virus infection.

Abstract The objective of this study was to examine the relationships among lymphocyte proliferation, interferon-γ (IFN-γ) production, and apoptosis in peripheral blood mononuclear cells (PBMC) of HIV-1-infected patients and controls. PBMC were prepared from 19 HIV-1-infected patients and 16 healthy controls. Using tetanus toxoid (TT) as a recall antigen, we assessed lymphocyte proliferation using [ 3 H]thymidine incorporation after 2, 4, 6, and 7 days' culture and IFN-γ production in 48-h culture supernatants by ELISA. Apoptosis was measured using TdT-mediated dUTP nick-end labeling. Median stimulation indices (SIs) in HIV-1-infected patients were 2.8 and 3.7 as opposed to 24.9 and 25.1 in healthy controls after 6 and 7 days' culture, respectively ( P P in vivo immune competence is unknown. Nonetheless, shorter duration assays may provide a more realistic estimate of the frequency of antigen-reactive cells in persons with HIV-1 infection.