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Infection of rAAV-AFP enhances immunostimulatory effect of human peripheral blood monocyte-derived dendritic cells

AIM: To study the immunostimulatory effect of rAAV-AFP (recombinant adeno-associated virus expressing α-fetoprotein antigen) transfection on dendritic cells (DCs) derived from human peripheral blood monocytes.

METHODS: Newly isolated dendritic cells were infected with rAAV-AFP. The percentage of viable DCs was observed by trypan blue exclusion every 24 h. After transfection, the alterations of surface markers on mature DCs, including CD80, CD86, CD83, CD40, CD1a, HLA-DR and α-fetoprotein (AFP), were detected by flow cytometry. Meanwhile, 3H-thymidine incorporation method was used to measure the capacity of T-cell proliferation before and after transfection. The specific killing activity of T cells was evaluated by MTT assay.

RESULTS: About 77.7% mature DCs expressed AFP protein. The viable DCs percentages and surface marker expression showed no significant changes after transfection (P > 0.05). Transfected DCs still had strong potential of stimulating the proliferation of T lymphatic cells, and there was no significant difference between transfected and non-transfected group (P > 0.05). Transfected DCs were capable of inducing specific killing effect on the target cells, and the activity was significantly higher than those in the non-transfected cells when the DCs and T cells were mixed at the ratios of 80:1, 40:1, and 20:1 (35.5 ± 5.5 vs 20.6 ± 4.7; 28.7 ± 3.6 vs 15.3 ± 2.5; 16.2 ± 2.8 vs 9.6 ± 1.8; all P < 0.01).

CONCLUSION: AFP gene, which is carried by recombinant adeno-associated virus, can be transferred into DCs with high efficiency. The function of mature DCs is not affected significantly by AFP transfection.