A NEW METHOD OF GENE-TRANSFER INTO HEMATOPOIETIC PROGENITORS USING LIQUID CULTURE WITH INTERLEUKIN-3 AND INTERLEUKIN-6

The technique of gene transfer into hematopoietic cells is expected to offer a new form of therapeutics. As a result of studies on a gene-delivery system using granulocyte-macrophage colony-forming units (CFU-GM), a type of hematopoietic progenitor, we have established a technique for efficient gene transfer into CFU-GM. DGL, a retrovirus vector containing the SV40 promoter and the neomycin resistance gene, was constructed and found to transfer genes effectively into murine CFU-GM, which subsequently expressed the neomycin resistance gene. After gene transfer of murine non-adherent bone marrow cells precultured in liquid culture with recombinant murine IL-3 (rmIL-3) and recombinant human IL-6 (rhIL-6) for 6 days, gene transferred CFU-GM in bone marrow cells were able to proliferate 5-10-fold and the ratio of gene transferred CFU-GM to total CFU-GM reached 70-100% from less than 1% in the liquid culture with rmIL-3, rhIL-6 and neomycin for 6 days. Using this protocol, we have been able to obtain large amounts of highly concentrated gene-transferred CFU-GM for fundamental research on CFU-GM gene-delivery systems.