489. Further Studies of the Most Efficient Vector Systems for Gene Transduction into Human Dendritic Cells Line (im-NMD)

Abstract

It has become evident that the specialized antigen presenting cells (APC), dendritic cells (DC), play a pivotal role in initiating a primary immune response. Furthermore it has been reported that several systems including Adenoviral vector, HVJ-related vector, and electroporation, are able to transduce the gene into DC and are able to modify the function of DC in mouse and human. However, our previous study demonstrated this is not the case with rat DC. To our best knowledge, there has been no direct evidence to support that currently-used vector systems are able to effectively transduce the gene into DC. Inasmuch as most, if not all, DC or DC-related gene transfer studies appeared to be performed by employing heterogeneous cell population, it is important to determine the extent of gene transduction into bona fide DC. In this study, employing recently established human DC cell line called im-NMD and enhanced green fluorescence protein (EGFP : Clontec-C1), we further examined a relative efficiency of each vector system into one of the DC lineage cell line. We provide further evidence that none of the currently-used vector systems are able to sufficiently transfer the gene into human DC cell line. In particular when the im-NMD is so driven by several cytokine combinations such as Flt3/Flk2 ligand and IL-6, and/or IL-4 and TNFa that they became mature DC phenotypes, it is indeed the case. Nevertheless, the most efficient transduction of the EGFP gene was observed under a long-term culture of im-NMD cell line. Hence the successful gene transfer was observed after one week culturing only with HIV-based lentiviral vector system. It should be noted that HVJ vector system that contained FITC-tagged random primers were indeed incorporated into the im-NMD. Thus it suggested that there are mechanisms that interfere the exogenous gene expression in bona fide DC.