Frequency and phenotyping of human immunodeficiency virus (HIV)-specific CD8+ T cells in HIV-infected children, using major histocompatibility complex class I peptide tetramers

Abstract

HLA-A*02 tetramers complexed to human immunodeficiency virus (HIV) Gag SLYNT-VATL and HIV Pol ILKEPVHGV peptides were used to characterize HLA class I-restricted CD8+ T cells in 41 HIV-infected children. The frequencies and the phenotype of specific circulating CD8+ T cells were determined in whole-blood samples by means of cytometric analysis. Background staining of 13 HLA-A*02-negative patients showed that the frequency of CD8+ T cells was <0.01%. Of the 28 HLA-A*02-positive patients, blood samples from 26 stained positive at least once the Gag tetramer (mean CD8+ T cells, 0.87%; range, 0.1%-3.9%), and blood samples from 21 stained positive for the Pol tetramer (mean CD8+ T cells, 0.59%; range, 0.1%-5.5%). The tetramer-binding cells were CD28-, CD45RA-, CD45RO+, HLA-DR+, and CD69- T lymphocytes. HIV-specific CD8+ T cells can be detected easily in peripheral blood of HIV-infected children, using HLA tetramers combined with HIV peptides. These cells are memory activated CD28-CD8+ T lymphocytes.