RESUMEN
Objective: To generate mouse B7-2 gene RNAi lentivirus and study its interference effects on B7-2 expression and T lymphocytes proliferation induced by dendritic cells. Methods: Three sequences specific targeting B7-2 gene and one non-specific sequence were respectively synthesized, and inserted into lentiviral vector, then the recombinant vectors were sequencing. 293 T cells were co-transfected with lentiviral expression plasmid and packaging plasmids to produce recombinant lentivirus which titre was checked according to the expression level of green fluorescent protein ( GFP). Bone marrow cells from C57 BL/6 mice were isolated to differentiate into DCs at the present of GM-CSF, IL-4 and LPS for 48 h, then morphology and phenotypic was identified. DCs were infected by recombinant RNAi lentivirus and then the efficiency of infection and the expression of B7-2 on the surface of DCs were detected by flow cytometry. Effects on the proliferation of T cells were detected by co-culturing with DCs which were infected by B7-2 RNAi lentivirus and murine spleen T cells in vitro. Results: DNA sequencing confirmed that three B7-2 RNAi and one non-specific recombinant lentiviral transfer plasmids were successfully constructed, the titer of recombinant lentivirus was ( 2-4) × 108 TU/ml. The recombinant lentivirus could effectively infect DC and inhibit the expression of B7-2. After the B7-2 recombinant lentivirus infection, the ability of DCs to stimulate the proliferation of T cells decreased obviously ( P＜0. 05). Conclusion: The lentiviral B7-2 gene RNAi vector can effectively silence the expression of B7-2 on the surface of DCs and inhibit the proliferation effect of T cells induced by DCs.