Role of the T cell receptor alpha chain in the development and phenotype of naturally arising CD4 +CD25 + T cells

Abstract

The T cell receptor alpha chain repertoire and the possible influence of the alpha chain on the development and phenotype of naturally arising mouse CD4 +CD25 + T cells have not been extensively analysed. We used all available Vα-specific monoclonal antibodies and a sensitive multiplex genomic DNA PCR assay to study the Vα repertoire of CD4 +CD25 + T cells in normal mice. To address whether CD4 +CD25 + T cells express two TCR alpha chains, we have carried out four-colour flow cytometry using combinations of the available anti-Vα reagents in mice where one allele of the TCRA locus had been inactivated. Results indicate that the Vα repertoire of CD4 +CD25 + T cells is as diverse as their CD25 − partners. In addition, CD4 +CD25 + T cells develop normally in Tcrα +/− mice and we show for the first time that despite expressing only one TCRα chain, they retain their characteristic CD4 low, CD3 low, TCRβ low, CD5 high, CD45RB low and cytoplasmic CD152 high phenotype.