Synergistic antitumor activity of chemotherapy and immunotherapy in the treatment of established rat solid tumors

Abstract

Objective To explore immunotherapy effective combined with active immunotherapy in different time according rats bearing-tumor after paclitaxel and carboplatin chemotherapy, and to identify the optimization time and strategy of vaccine and seek rational chemo-immunotherapy strategies in ovarian cancer treatment. Methods The dynamic immunocytes number and function in established tumor treated with paclitaxel and carboplatin chemotherapy were investigated. The changes of established tumor volume and immune function of different groups were observed according to combining different time after chemotherapy and vaccine. Results Lymphopenia was observed and the number of lymphocyte subset decreased remarkably on the 6th day, but all cells were found almost recovered on 15th day after chemotherapy. There is the process of immune-enhancing from post-chemotherapy 6 day to 10 day and reversal of immune suppression temporary. The combination post-chemotherapy 6 day with CTL caused a significantly delayed tumor growth in both tumor models and induced significant the proliferation of T lymphocyte by [H] 3 releasing. The number of CD8+T cell is the highest, but the expression of Tr cell was lowest in the group of post-chemotherapy 6 day with CTL. Furthermore, the ability of CD8+T secretion IFN-γ is the most in the post-chemotherapy 6 day with immunotherapy groups. Conclusion Combinational paclitaxel and carboplatin chemotherapy has synergistic effects with active immunotherapy boosting against tumor during window periods, where 6 days after chemotherapy with the most decreased number of lymphocytes in the animal periphery might represent the optimal checkpoint for the immune therapy against tumors. Therefore, monitoring the immune status of tumor patients might become one of the important prerequisites for the effective immune therapy when designing the comprehensive therapeutic strategies. Key words: Paclitaxel; Carboplatin; Ovarian cancer; Immune function; Active immunotherapy