T cell receptor Vβ repertoire of the antigen specific CD8 T lymphocyte subset of HIV infected children

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Abstract
Objective Analysis of the T cell receptor Vβ repertoire during HIV infection reveals expansions in multiple Vβ families of CD8 T cells, but their antigenic specificity is ill-defined. We sought to determine the TCR Vβ repertoire of HIV specific CD8 T lymphocytes in infected children. Design/methods We performed flow cytometry to examine TCR Vβ families as identified by specific monoclonal antibodies and binding of HIV peptide loaded tetrameric MHC complexes in peripheral blood samples from a group of HIV infected children. Results Simultaneous assessment of 12 selected expanded Vβ families amongst nine HIV infected patients for tetramer binding revealed only one child in whom the expanded Vβ population bound HIV Gag or Pol tetramers. In four HIV infected children, percentage tetramer binding cells was determined in 21 TCR Vβ families. The tetramer binding cells of three children exhibited a widely distributed TCR Vβ repertoire while in the fourth patient they were preferentially localized within two TCR Vβ families. Repeat analysis revealed that the TCR Vβ repertoire of tetramer binding cells was stable. Conclusions These data provide evidence that the HIV-specific CD8 T cell response in children is usually distributed widely among many different TCR Vβ families. The heterogeneity of the TCR Vβ repertoire usage by the antigen specific CD8 T cells may reflect the dynamic interaction between host and pathogen during the course of HIV infection and may be influenced by the rate of viral mutation, CD4 T cell helper activity, or other factors.