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 SLYNTVATL 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 + 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