Infection of human hematopoietic progenitor cells using a retroviral vector with a xenotropic pseudotype.

In an effort to determine if viral envelope type influences the infectivity of human hematopoietic progenitor cells with retroviral vectors, we have pseudotyped the retroviral vector N2, which confers G418-resistance, in either an amphotropic or xenotropic envelope. Vector titres obtained by the pseudotype procedure were nearly two orders of magnitude lower than the titer obtained when N2 was packaged using the amphotropic PA317 packaging cell line. Despite its low titer, xenotropically pseudotyped N2 generated G418-resistant hematopoietic colonies at levels approaching those observed after bone marrow was infected using vector packaged using PA317 cells. These results suggest that manipulations of vector envelope may lead to improvements in the level of infection of human hematopoietic stem cells.