Mycobacterial Ag85A-Ag85B double gene adenovirus inhibits lewis lung cancer growth in mice

Background: Immunotherapy is the most promising novel treatment for cancer and expected to achieve breakthrough in near future because of improvement in the understanding of the tumor immunology. The present study is aimed to pave way to explore possibility and approaches of active immunotherapy for lung cancer based on DNA vaccines containing antigen genes of mycobacterial Ag85A and Ag85B. Methods: Mycobacterial antigen genes adenovirus Ad-Ag85A-Ag85B-CMV was constructed. Lewis lung cancer (LLC) cells were infected with Ad-Ag85AAg85B-CMV and then Ag85A and Ag85 expression was detected with Western blot. Splenocytes of C57BL/6 mice that were vaccinated with Bacillus Calmette-Guerin (BCG) 6 weeks before were separated and co-cultured with AdAg85A-Ag85B-CMV infected LLC cells. Interleukin-2 (IL-2) and interferon-γ (IFN-γ) in co-culture medium was detected by enzyme-linked immunosorbent assay (ELISA). LLC bearing mice were developed with C57BL/6 mice vaccinated with BCG 6 weeks before. Then, Ad-Ag85A-Ag85B-CMV was intra-tumorally injected so that its inhibitory effect for LLC in mice could be observed. Results: Mycobacterial antigens of Ag85A and Ag85B were detected in Ad-Ag85AAg85B-CMV transfected LLC cells with Western blot. An elevation of IL-2 and IFN-γ in co-culture medium was detected by ELISA, compared with empty adenovius and blank control. Average weight of tumors in mice of BCG vaccination and Ad-Ag85A-Ag85B-CMV treatment group was significantly lower than control groups. Conclusion: Immune gene-therapy using mycobacterial antigen genes of Ag85A and Ag85B is promising novel treatment for lung cancer.