A ROLE FOR CD81 IN EARLY T-CELL DEVELOPMENT

Early stages of T cell development are thought to include a series of coordinated interactions between thymocytes and other cells of the thy mus. A monoclonal antibody specific for mouse CD81 was identified that blocked the appearance of alpha beta but nor gamma delta T cells in f etal organ cultures initiated with day 14.5 thymus lobes. In reaggrega tion cultures with CD81-transfected fibroblasts, CD4(-)CD8(-) thymocyt es differentiated into CD4(+)CD8(+) T cells, Thus, interactions betwee n immature thymocytes and stromal cells expressing CD81 are required a nd may be sufficient to induce early events associated with T cell dev elopment.