The Constructions Of MAGE-4 And Heat Shock Protein 70 Fusion DNA Vaccine And Their Antitumor Effects Invivo

Malignant tumor is a kind of comman and frequently encountered diseases which harm human health seriously now. There are about 8,000,000 people in the whole world and 2,000,000 people in china who die of malignant tumor. How to prevent and cure this disease has becom an increasing concerned problem to people.Conventional therapies to malignant tumor include operation, radiotherapy and chemotherapy. Clinical workers have made tremendous progresses in prolonging lives of patients and increasing their survival qualities through improving modus operandi, adjusting radiation dose and upgrading chemotherapy schedule. With the development of molecular bilolgy and immunology, biotherapy to tumor has become the forth treatment. Biotherapy is a special therapeutics which regulate growth, differentiation, apoptosis, infestation and metabasis of tumor. The differences between tumor cell and normal cell are based on gene and protein expression levels. Vaccine biotherapy is the important method of tumor biotherapy. Vaccine biotherapy can induce initiative and specific immune responses.The identification of tumor specific antigen is the key to induction of specific antitumor immunity. MAGE-4 is a member of MAGE family. MAGE-4 is one of the tumor-specific antigens. MAGE-4 doesn' t express in normal tissues except testis and placenta. So MAGE-4 is regarded as an ideal target for specific antitum or immunotherapy. However, there is still a need to enhance the potency of MAGE-4 vaccines. Heat shock protein 70(HSP70) is one kind of molecular chaperones which has highly conservative protein sequences. HSP70 expresses in both prokaryote and mammal cells. Not only can HSP70 regulate the physiological function of cells in stress state, but also can process and presentate proteins. Recent researches discover that HSP70 is a powerful immunologic adjuvant which play an important role in immunoreaction. Above all, these investigation have made HSP70 more attractive for use in immunotherapy.This study has amplified MAGE-4 gene and HSP70 gene from human colon adenocarcinoma by reverse transcription-polymerase chain reaction. Then we constructed eukaryotic expressing plasmids of pcDNA3.1/MAGE-4, pcDNA3.1/HSP70 and fusion expressing plasmid of pcDNA3.1/HSP70/MAGE-4 correctly. We also constructed MAGE-4 expressing CT26 cell lines. The mice were immunized by plasmids mentioned above and spleen lymphocytes were separated. The result revealed that fusion vaccine can increase lethal effect to CT26/MAGE-4 cells. We detected IL-2 and IFN-γlevels from mixed culture of immunized mices'spleen lymphocytes and CT26/MAGE-4 cells. The result proved that the levels were higher than other groups which comparede with fusion vaccine group. The fusion expressing plasmid of pcDNA3.1/HSP70/MAGE-4 can inhibit growth of CT26/MAGE-4 cells in mices' tumor models, and prong live times of those mices. Above all, it can be concluded that Compared with antigen-alone vaccines, co-inoculated vaccine and control group, fusion DNA vaccine can induce specific immune response effectively.