Quantification of CD8⁺ T lymphocytes responsive to human immunodeficiency virus (HIV) peptide antigens in HIV-infected patients and seronegative persons at high risk for recent HIV exposure

The combination of a tumor necrosis factor (TNF)-α enzyme-lined immunospot (ELISPOT) assay and computer-assisted video image analysis was used to detect and quantitate in peripheral blood CD8⁺ T cells reactive with known human immunodeficiency virus type 1 (HIV-1) peptide antigens presented by HLA-A2 or HLA-A3. T lymphocyte responsiveness to at least one HIV peptide was found in 10 (83%) of 12 HIV-A3. T lymphocyte responsiveness to at least one HIV peptide was found in 10 (83%) of 12 HIV-1-infected patients and in 5 (45%) of 11 persons who had no serologic and virologic signs of HIV infection but who were at high risk for recent sexual exposure to HIV-1. CD8⁺ T cells responding to HIV-1 peptides were observed in none of 11 HIV-seronegative donors without a history of HIV exposures. ELISPOT assays are relatively fast and easy to perform and appear to reliably detect T cell reactivity due to previous exposure to HIV. These findings support the use of the ELISPOT assay for monitoring T cell responsiveness to HIV peptides.