Gene transfer into human dendritic antigen-presenting cells by vaccinia virus and adenovirus vectors

In a search for means to deliver exogenous gene(s) into human dendritic cel ls (DCs) from the perspective of tumor-specific vaccination, we have evalua ted two recombinant viruses, both of which carry a reporter gene which is n amely a modified vaccinia virus Ankara (MVA) and an adenovirus, as possible expression vectors. The recombinant MVA-P11LZ vector carries the Escherich ia coli lacZ gene coding for the enzyme beta-galactosidase, and the recombi nant Ad-MFG-AP vector carries a modified membrane-exposed alkaline phosphat ase (AP) gene. DCs were generated ex vivo in the presence of tumor necrosis factor-alpha, granulocyte macrophage colony-stimulating factor, stem cell factor, and flk-2/flt-3 ligand taken from CD34(+) hematopoietic progenitors that were mobilized into the peripheral blood of cancer patients treated w ith high-dose cyclophosphamide and filgrastim. The target cells used for ge ne delivery were either CD34(+) cells that had been subsequently induced to differentiate into mature DCs or DCs transduced after ex vivo generation f rom CD34(+) cells. The results showed that: ia) infection of CD34(+) cell d erived-DCs (mature DCs) with either viral vector resulted in the efficient synthesis of recombinant protein, and ib) CD34(+) cells were permissive for the expression of the recombinant reporter gene after infection with Ad-MF G-AP but not after infection with MVA-P11LZ. In conclusion, these results s uggest that vaccinia and adenovirus vectors are candidate to act as vehicle s in genetically engineering human DCs.