RESUMO
Objective: To evaluate the efficacy of 3LL/GM-CSF tumor vaccine combined with pacilitaxel chemotherapy in treatment of mice bearing transplanted Lewis lung carcinoma. Methods: The tumor vaccine 3LL/GM-CSF was prepared by infecting Lewis lung carcinoma cell line 3LL with adenovirus encoding GM-GSF. Mice model of Lewis lung carcinoma was established by subcutaneous injection of 2?104 3LL cells into C57BL/6(H-2b)mice. The sensitivity of Lewis lung carcinoma cell line-3LL to the treatment of pacilitaxel was detected in vivo and in vitro. The mice tumor model was first treated with pacilitaxel chemotherapy and then with 3LL/GM-CSF, or first with 3LL/GM-CSF and then with pacilitaxel. Tumor growth and the long-term survival of mice were observed after treatment. The immune memory and cytotoxicity against target cells were studied in the mice. Results: Pacilitaxel at 100 nmol/L killed 32.10% 3LL cells after 24 hour in vitro; but pacilitaxel at 5-25 mg/kg only had a poor effect on growth of 3LL cells in vivo. The tumors rebated in 70% of mice treated with pacilitaxel chemotherapy and 3LL/GM-CSF vaccination successively, and the survival of these mice was obviously longer than that of pure pacilitaxel chemotherapy group (70.0 days vs 27.5 days). The killing rate of 3LL/GM-CSF after pacilitaxel chemotherapy was 41.35% on day 3. Meanwhile, the survival mice could resist the re-attack of 3LL cells (2?104). We also noticed that first treatment with 3LL/GM-CSF and then pacilitaxel chemotherapy had no effect on tumors. Conclusion: Application of tumor vaccine shortly after pacilitaxel chemotherapy can induce specific immune responses and prolong the survival of experimental mice, which provide a basis for future clinical practice.