T-cell Immunity Against Epstein-Barr Virus (EBV) Associated Tumors In Vivo Induced By Dendritic Cells Transfected With EB Virus Virus Latent Membrane 2A (LMP2A) Recombinant Adenovirus

Objective: To establish an animal model implanted with EB virus LMP2A expressing tumor. To assess the feasibility and efficacy of T-cell immunity against Epstein-Barr virus (EBV) associated tumors in vivo induced by DCs transfected with EBV LMP2A recombinant adenovirus for the clinical application of the DC-based immunotherapy in EBV associated tumors.Methods: The EB virus LMP2A was cloned into retrovirus vector pLXSN. The recombinant vector was transfected into BALB/c mice derived SP2/0 cells by Clonfectin and then cells were screened by G418 to get positive clones and amplified. Positive cells were identified by means of PCR test; RT-PCR; IFA; FACS. Those cells were injected into of BALB/c mice to establish tumor animal model. The tumors was removed after 2 weeks and subjected to histological examination (H&E stain). According to Inaba's methods, Bone marrow-derived DCs were induced. The surface molecules of DCs are tested by FACS. The function of DC to stimulate allogeneic T cells proliferation was measured by MLR. DCs transfected with EB virus LMP2A recombinant adenovirus were infused into BALB/c mice. Splenic cytotoxic T-cell responses were measured by LDH release detection and interferon-γ production was also tested by ELISA. And in vivo immune protection of DCs in mice tumor models was studied.Results: The retrovirus vector containing LMP2A gene was constructed. The SP2/0 cells expressing LMP2A were established. Those LMP2A-expressing SP2/0 cells can become tumors in BALB/c mice. DCs transfected with EBV LMP2A recombinant adenovirus could remarkably induce EBV LMP2A specific cytotoxic T-cell responses andinterferon-y production in vivo. Vaccination of these DCs was able to lead to prolongation in overall survivals and retard the tumor growth in mice tumor models.Conclusion: The EBV LMP2A gene was integrated into SP2/0 cells and could be expressed by them. The mice models implanted with EBV LMP2A expressing tumor were established. DCs transfected with EBV LMP2A recombinant adenovirus could remarkably induce EBV LMP2A specific cytotoxic T-cell responses and interferon-y production in vivo. Vaccination of these DCs was able to lead to prolongation in overall survivals and retard the tumor growth in mice tumor models. The results supported that DCs transfected with EBV LMP2A recombinant adenovirus is a feasible and effective method to elicit specific cytotoxic T-cell responses against EBV LMP2A in vivo for treatment of EBV associated tumors. The study may be useful to the clinical application of the DC-based immunotherapeutic approach to EBV associated tumors.