By creating an off-the-shelf T-cell progenitor bank from umbilical cord blood CD34+ cells, the therapeutic cell product would become immediately available to patients in need, independently of the donor, even when allogeneic HSCT is not possible (e.g., following lymphodepleting chemotherapy, in aging patients as protection against viral infections, or in the context of immunosuppressive therapy). Here, CD34 is linked to viral infectious disease.