T-CELL REPERTOIRE AND CLONAL DELETION OF MTV SUPERANTIGEN-REACTIVE T-CELLS IN MICE LACKING CD4 AND CD8 MOLECULES

CD4(-)CD8(-) double-negative T cells constitute a lymphocyte subpopula tion within the thymus and peripheral lymphatic organs that express a unique T cell receptor (TCR) repertoire and do not undergo negative se lection. To test whether these cells develop as a distinct lineage or due to altered selection in the absence of CD4 and CD8 expression, we analyzed the TCR repertoire in mice lacking both CD4 and CD8 accessory molecules after homologous recombination (CD4(0/0)CD8(0/0)). We show that mature T cells of CD4(0/0)CD8(0/0) mice express an unbiased diver se TCR VP repertoire comparable to wild type mice. In addition, clonal deletion of mouse mammary tumor virus superantigen-reactive T cells d id occur in CD4(0/0)CD8(0/0) mice. These data show that the intrinsic lack of CD4 and CD8 expression has no effect on the mature TCR reperto ire and that clonal deletion of superantigen-reactive cells is indepen dent of CD4 and CD8 co-receptors.