BIASED EXPRESSION OF INDIVIDUAL T-CELL RECEPTOR V-GENE SEGMENTS IN CD4+ AND CD8+ HUMAN PERIPHERAL-BLOOD LYMPHOCYTES-T

The expression of seven different alpha and beta gene segments of the T cell receptor on normal human CD4+ and CD8+ T lymphocytes, respectively, was examined using V gene-specific monoclonal antibodies. We found a statistically significant (p < 0.001) bias of the expression of four V gene products towards the CD4+ subpopulation. In every individual analyzed, the V-beta-5.1 gene segment was expressed to a higher degree among CD4+ compared to CD8+ cells, with a median value of 4.8% among CD4+ cells and 1.5% among CD8+ cells. There was also a statistically significant skewness in the usage of the V-beta-6.7, V-beta-8 and V-beta-12 gene segments towards the CD4+ T cell population, but not as dominating as for the V-beta-5.1. Lymphocytes from umbilical cord blood showed similar skewed reactivities for the V-beta-5.1, V-beta-6.7 and V-beta-12-specific monoclonal antibodies. Aspects of positive and negative selection, as possible explanations for these findings, are discussed.