Efficient gene transduction by RGD-fiber modified recombinant adenovirus into dendritic cells

Dendritic cells (DC) are important antigen-presenting cells in the development of an anti-tumor T cell response. To extend the range of current immuno/gene therapies, we tested luciferase-expressing RGD-adenovirus (Ad) (Ad5lucRGD)-mediated transduction into DC. Phenotypically characterized DC were generated from peripheral blood CD14⁺ cells by incubation with granulocyte-macrophage colony-stimulating factor, interleukin-4 and tumor necrosis factor α. On the 7th day of culture, the cells became mature DC with a CD1a⁺, CD11c⁺, CD80⁺, CD83⁺, Cd86⁺, human leukocyte antigen (HLA)-DR⁺, CD14^- phenotype. The expression of α_vβ₃ integrin was enhanced on day 3 and returned to the basal level on day 7. We then compared the transduction efficiency of an Ad5lucRGD system to that using conventional Ad, in cells harvested on days 1, 3 and 7 of culture. Luciferase activity was negligible in AdCMVLuc, but remarkable in cells processed with Ad5lucRGD. Activity was maximal in cells that had been cultured for 3 days. Recombinant Ad5 fiber knob protein blocked AdCMVLuc- and Ad5lucRGD-mediated gene transduction by 90% and 20%, respectively. Surface markers and cytokine production were not affected by Ad5lucRGD-mediated transduction.