Thymocyte progenitors in ageing.

The effect of ageing on thymocyte progenitors in the bone marrow was studied in an in vitro experimental model that permits T lymphocyte development. The model is based on co-culture of BM cells from young and old mice with lymphoid depleted fetal thymus explants. We applied different strategies of thymic colonization, including competitive colonization by BM cells from different donor age groups and MHC backgrounds. Our data reveal intrinsic changes in the BM that lead to manifestation of immunosenescence in the T lymphocyte compartment.