Retrovirus mediated transfer and expression of GM-CSF in haematopoietic cells

Two retrovirus vectors were compared for their ability to express granulocyte-macrophage colony stimulating factor (GM-CSF) in a haematopoietic cell line, FDCP1, which is dependent on GM-CSF for survival. Both a MoMLV-based vector pVneoGM, and a MPSV-based vector, M3neoGM, were found to be capable of transmitting and expressing both GM-CSF and neomycin sequences in the myeloid FDCP1 cell line. Our results also demonstrate that pVneoGM is more efficient at generating GM-CSF independent colonies than M3neoGM. Analysis of cell lines derived after infection confirmed pVneoGM expressed higher levels of GM-CSF. Cell lines generated by infection with pVneoGM responded to levels of exogenous recombinant GM-CSF which did not stimulate growth of the parental cell line, suggesting autocrine stimulation may convey a proliferative advantage under sub-optimal growth conditions. Finally the parental vectors pVneo and M3neo were shown to be capable of expressing the neomycin gene in both murine haematopoietic progenitor and stem cells.