Immunodeficient mice as models of human hematopoietic stem cell engraftment

The past year has brought forth some exciting developments in the use of murine xenotransplantation systems to study the biology and transduction of human hematopoietic stem cells. The effects of cytokines have been studied by injection into the mice or by treatment of the cell inoculum prior to injection. The importance of the cell cycle and integrin expression has been evaluated. New methods of gene therapy have been tested in xenograft models — including cell cycle manipulation and a promising new lentiviral vector system, based on HIV.