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

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) is a negative-strand RNA virus and has recently been used for the gene therapy vectors, SeV vectors (SeVV), for somatic gene therapy. This vector does not have potential of stable transformation of target cells because they generate no DNA intermediates and therefore are unable to integrate. Also, SeVV has been shown to ensure efficient expression of foreign genes in various types of tissues and can be used 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 24 hours in vitro. To do the in vivo preclinical experiments, we also transduced cDNA of GFP and 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.