OBJECTIVETo evaluate the immunostimulatory capacity of human peripheral blood dendritic cells (DCs) with Her2/neu gene transfection mediated by adeno-associated virus.

METHODSThe HLA genotypes of the breast cancer cells SK-BR-3 and MCF7 were determined, and the mononuclear cells from healthy donors with matching HLA genotype were isolated by Ficoll-Hypaque density gradient separation. The isolated cells were divided into two groups with or without transfection with the recombinant virus harboring Her2/neu gene. The cells were cultured for 7 days in RPMI 1640 medium supplemented with 10% AB human serum, GM-CSF, interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-alpha). The mature DCs were then harvested from the cell culture and their phenotypes were identified using flow cytometry. MTT assay was employed to examine the specific killing activity of the T cells induced by the DCs.

RESULTSThe DCs transfected with the recombinant adeno-associated virus expressed CD1a, CD86 and CD83 at the rate of 98.10%, 99.42%, and 84.59%, and those without the viral transfection expressed the markers at the rate 92.69%, 98.07%, and 82.72%, respectively, showing no obvious differences in the phenotypes of the two DCs. The transfected DCs, however, showed markedly higher expression rates of CD40 and CD80 than the non-transfected DCs (61.02% vs 36.19%, and 97.61% vs 55.5%, respectively). The DCs, irrespective of the transfection, showed comparable capacities in stimulating T cell proliferation. The transfected DCs exhibited the capacity of inducing the T cells to specifically kill the target tumor cells, with the highest killing rate of (39.7-/+7.2)%.

CONCLUSIONThe immunostimulatory capacity of human peripheral blood DCs are enhanced by Her2/neu gene transfection mediated by adeno-associated virus.