ABSTRACT
Objective:To investigate the effect of gemcitabine on myeloid derived suppressor cells (MDSC) in the spleen of B lymphoma cell-bearing mice, and the therapeutic effect of gemcitabine combined with intratumoral injection of dendritic cells (DCs) in treatment of large B lymphoma. Methods: BALB/c mice were inoculated subcutaneously with B lymphoma A20 cells; large tumors were formed 30 d after inoculation. Gr-1~+ CD11b~+ MDSC proportion in the spleen was analyzed by flow cytometry before and after gemcitabine treatment. Splenic MDSC sorted by immunomagnetic beads was further treated with gemcitabine, and then the apoptosis of MDSC was examined by Annexin-V/PI staining. Tumor growth and survival time of A20 tumor-bearing mice were observed after treatment with gemcitabine and intratumoral injection of DCs. Results: Splenic Gr-1~+ CD11b~+ MDSC ratio in A20 cell-bearing mice was 10 times higher than that in the normal mice. Gemcitabine induced apoptosis and necrosis of purified MDSC in vitro in a time-dependent manner. The percentage of MDSC in the spleen of A20 tumor-bearing mice was decreased after injection of a single dose of gemcitabine. Gemcit-abine or intratumoral injection of DCs alone inhibited growth of tumor to a certain degree, with the mean survival periods of mice in the gemcitabine, DCs, and untreated groups being (48.8±3.6) d, (47.2±7.4) d, and (38.8±2.2) d, respectively. Gemcitabine chemotherapy combined with intratumoral DC injection resulted in continuous shrink of the tumors, and 60% of the mice survived for more than 90 d. Conclusion: Gemcitabine can effectively eliminate splenic MDSC in tumor-bearing mice. Gemcitabine chemotherapy and DCs immunotherapy can work synergistically in the treat-ment of huge lymphoma. These results provide an experimental basis for the comprehensive chemotherapy and immunotber-apy of relapsed or refractory lymphoma.
ABSTRACT
Due to therapeutic regimens for patients with malignant lymphoma (ML) is currently unsatisfactory, it is important to develop new complementary therapies for longer disease-free survival. Dendritic cells (DC) are specialized antigen-presenting cells of immune system and vaccination with tumor antigen-pulsed DC has been applied to treat patients for ML. In this review, we summarize various types of ML-associated antigens and clinical trials on DC-based immunotherapy in ML, and discuss the development of DC immunotherapy for ML patients in future.