Infection of stromal and hemopoietic precursor cells with lentivirus vector in vivo and in vitro.

We developed a method for gene transfer into mesenchymal stromal cells. Lentivirus vector containing green fluorescent protein gene for labeling stromal and hemopoietic precursor cells was obtained using two plasmid sets from different sources. The vector was injected into the femur of mice in vivo and added into culture medium for in vitro infection of the stromal sublayer of long-term bone marrow culture. From 25 to 80% hemopoietic stem cells forming colonies in the spleen were infected with lentivirus vector in vivo and in vitro. Fibroblast colony-forming cells from the femoral bones of mice injected with the lentivirus vector carried no marker gene. The marker gene was detected in differentiated descendants from mesenchymal stem cells (bone cavity cells from the focus of ectopic hemopoiesis formed after implantation of the femoral bone marrow cylinder infected with lentivirus vector under the renal capsule of syngeneic recipient). In in vitro experiments, the marker gene was detected in sublayers of long-term bone marrow cultures infected after preliminary 28-week culturing, when hemopoiesis was completely exhausted. The efficiency of infection of stromal precursor cells depended on the source of lentivirus. The possibility of transfering the target gene into hemopoietic precursor cells in vivo is demonstrated. Stromal precursor cells can incorporate the provirus in vivo and in vitro, but conditions and infection system for effective infection should be thoroughly selected.