478. Novel Gene Delivery System of Sendai Virus Vector-Transduced Human Peripheral Monocytes

Abstract

Extensive monocytes extravasation is seen in infection sites, inflamed tissue and tumor tissues and exhibit a tissue-specific range of functions including phagocytosis, antigen presentation to T cells, and the release of a wide array of cytokines, chemokines, enzymes and nitrogen species. As monocytes have natural tropism to such tissues in each disease condition, these cells can be used as novel gene delivery system to cure the condition. On the other hand, as monocytes are quiescent cells, available gene transfer vectors are limited. Sendai virus (SeV) belonging to the Genus Respirovirus infects and multiplies its genome copy in most mammalian cells, and it has recently been used for the gene therapy vectors, SeV vectors (SeVV), for somatic gene therapy. This vector that expresses high-level of transgene does not have a DNA phase during its life cycle, so it does not need to be concerned about the transformation of cells by integration of vector materials into the host chromosomes, the genotoxicity-free nature. Thus, we used SeVV for gene transfer into monocytes. We first of all studied the gene transduction efficiency of SeVV into human peripheral blood CD 14 positive monocytes using GFP gene as a marker. About 82% of monocytes became GFP positive, whereas only 23% of lymphocytes and 1.8% of granulocytes became positive. The transduction efficiency was peaked at M.O.I.=1. The expression level was at least preserved for 16 hours in vitro. To do the in vivo preclinical experiments, we also transduced cDNA of GFP or GDNF (glial cell line-derived neurotrophic factor) into the peripheral monocytes of Macaca fascicularis monkey and high level expression of these genes were obtained. In vitro monocyte function after gene transduction are now under investigation. SeVV is considered to be promising gene transfer vector for primate monocytes.