Post- thymic in vivo expansion of mature alpha beta T cells.

To discriminate whether peripheral T cell expansion is a property of pluripotent T cell precursors or of T lymphocytes precommitted to the expression of a single T cell receptor, we have evaluated the repopulation capacity of T lymphocytes expressing defined V beta gene products after transfer into syngeneic nude mice. The results showed no difference in the expansion potential of cells expressing different V beta s. The frequency of cells bearing different V beta gene products in the donor and the expanded cell populations are very similar, even when sorted populations enriched or deleted in T cells expressing a defined V beta gene product were used as a source of donor cells. These results demonstrate that peripheral T cells expressing alpha beta TCR are fully competent of extensive division in the peripheral pools.