Transient T cell receptor beta-chain variable region-specific expansions of CD4(+) and CD8(+) T cells during the early phase of pediatric human immunodeficiency virus infection: Characterization of expanded cell populations by T cell receptor phenotyping

T cell receptor (TCR) repertoire perturbations ape commonly detected in CD8 (+) T cells during adult primary human immunodeficiency virus (HIV) infecti on and have been associated with HN-specific cytotoxic T cell responses, By use of flow cytometry, transient high-level TCR beta-chain variable region -specific expansions of CD4(+) and CD8(+) T cells were observed more freque ntly in HIV-infected children than in children exposed to HIV who remained uninfected. TCR beta-chain diversity analysis and diversity-specific polyme rase chain reaction were used to study the clonality of expanded CD4(+) and CD8(+) subsets. In CD8(+) T cells, structural features of the complement-d etermining regions 3 were altered during the course of the expansion, and p ersistent TCR clonotypes were observed, consistent with antigen-driven sele ction. In contrast, TCR beta-chain variable region-specific expansions with out clonotypic overrepresentation or persistence were observed in CD4(+) T cells, possibly related to HIV-specific helper T cell responses or to the p rogressive destruction of the CD4(+) cell compartment.