Generation of functional thymocytes in the human adult

Reconstituting the immune response will be critical for the survival of HIV -infected individuals once viral load is brought under control. While the a dult thymus was previously thought to be relatively inactive, new data sugg est it may play a role in T cell reconstitution. We examined thymopoiesis i n adults up to 56 years of age and found active T cell receptor (TCR) rearr angement, generating a diverse TCR VP repertoire. The resulting thymocytes are functional and are capable of responding to costimulatory signals. Thes e data demonstrate that the adult thymus remains active late in life and co ntributes functional T cells to the peripheral lymphoid pool.