Study Of Antibody-coated Tumor Cell Vaccine

Our study is to clone the extracellular and transmembrane domains (ECD and TMD) of human CD20 and construct its eukaryotic expression vector for the evaluation of the possability of antibody coated tumor cell vaccine therapy in animal model. The desired result is to provide antigens in a stimulatory immunotherapy which allows the in vivo generation of a potent anti-tumor immune response.The whole cDNA was amplified by RT-PCR method from the Raji cells and cloned to the downstream of expression vector pcDNA 3f-sig with a signal pepetide. The fragment was identified by enzyme digestion and DNA sequencing. Cells stably expressing sig-CD20 were established by screening with G418 after transfection and characterization of the transfected B16F10 cell line were rightly evaluated by indirect immunoflurescence assay and FACS. To further explore the rituximab mediated antitumor effect, a Rituximab modified tumor cell vaccine which had been inactivated by mitomycin C(MMC)was developed and treated in its syngeneic C57BL/6 mice model effectively. The results demonstrated that the Rituximab-coated tumor cell vaccine had a significant therapeutic effect against tumor pulmonary metastasis formation. The CTLs activity was remarkably higher from the mice vaccinated by Rituximab-coated tumor cell vaccine than normal Ig-coated tumor cell vaccine. Capture rate of tumor cells by DCs, which were detected by flow cytometry, was increased by adding Rituximab. The tumor specific cytolysis could be induced by Rituximab-coated tumor cell in human in vitro assay. Human tumor specific CTLs could also be highly induced by Rituximab-coated tumor cell vaccine. It was inhibited by anti- HLA-A2 site monoclonal antibody. This therapeutic strategy provides a simple way to potentialize CTLs function to combat cancer and may promote more clinical consideration in immunotherapy for tumors. Rituximab-coated tumor cell vaccine also expanded the clinical Rituximab applications.