Anti-tumor mechanisms of lymphopenic mice transferred with tumor-specific lymphocytes and immunized with mIL-21 tumor vaccine
Objective To explore the mechanism of anti-tumor effects of transferring tumor-specif-ic lymphocytes obtained from pre-immunized BALB/c mice with inactive rolL-21 tumor vaccine (mIL-21-Sp2/0)to syngeneic mice, associated with mIL-21 tumor vaccine immunization, in the condition of cyclo-phosphamide (Cy)-induced lymphopenia. Methods Activated lymphocytes of spleen and lymph nodes ob-tained from pre-immunlzed syngeneic mice with irradiated mIL-21-Sp2/0 cells were infused into BALB/cmice treated with Cy 2 days before, subsequently vaccinated with mlL-21 tumor vaccine, after 7 days, chal-lenged with Sp2/0 tumor cells, observed the growth of tumor of mice. T lymphocyte subsets differentiation was measured by flow cytometry (FCM) analysis. The proliferation and cytotoxie activities of activated lym-phocytes were analyzed by FCM, respectively, staining with CFSE and 7-AAD. The number of IFN-γ-secre-ting cells was evaluated by ELISPOT. Results The lymphopenic mice were transferred with activated lym-phocytes and inoculated with raiL-21 tumor vaccine might provide superior anti-tumor immunoprotection, re-tard tumor growth of the mice. The proliferating capabilities and killing rate of transferred tumor Ag-specific lymphocytes enhanced obviously, the number of IFN-γ-secreting cells was significantly higher compared with the control groups. Conclusion Under Cy-induced lymphopenia condition, tumor Ag-specific lymphocytes sensitized by raiL-21 tumor vaccine were transferred to mice and immunized with mlL-21 tumor vaccine at the same time, benefit the proliferation of transferred effective cells and immune cells itself, assist to form and sustain special anti-tumor effects. 
 
Key words: 
mIL-21 tumor vaccine;  Adoptive immunotherapy;  Lymphopenia-induced prolifera-tion;  Anti-tumor effects