| Malignant tumor is one of the most important killers which threaten the health of people all over the world. Only malignant tumors have been cured effectively can we make a great progress in the health service of human beings. There will be about 2,000,000 people in China who suffered from neopathy of cancer and there are 1,500,000 people will die of malignant tumors. The therapy of malignant tumors would be the number one topic in the development of health service in China.Operation therapy, radiation therapy and chemotherapy are the principle therapeutics for the malignant tumors currently. Operation therapy is the most commonly used methods to deal with cancer and can achieve a satisfying effect in many malignant tumors which arise locally early. But the operation therapies cannot get a satisfying result or even cannot be performed in the malignant tumors which have diffused such as leukemia and tumors inadvanced stage and in the malignant tumors which infiltrate important organs and transferred delitescencely to distant place. Radiation therapy and chemotherapy can also kill and wound the normal tissue and produce great side effects. Resistance to the drugs can also limit the application of chemotherapy. The currently therapies cannot be satisfying in the treatment for the malignant tumors.The biological behaviors of malignant tumors have been recognized more deeply along with the rapidly development of molecular biology, immunology and biochemical in the past few years. Malignant tumors are one kind of gene associated diseases and tumor cells are not only similar and homological but heterological with normal tissue. The cells of malignant tumors can escape from immunologic surveillance and immune clearance and a different process of immune response has happened. The tumor vaccines can kill and eliminate the tumor cells by utilization of the tumor cells' heterogeneity and the vaccines' different response to normal cells, and have few affect to normal tissues. Some of tumor vaccines have administrated to the third clinical research and an inspiring progress has been made.In 1991, researchers first isolated a melanoma-associated antigen (MAGE) gene, MAGE-1. This antigen which has been isolated from an MZ-2 human melanoma cell line could be recognized by cytotoxic T lymphocytes (CTLs). In the following years, dozens of mew MAGE gene were identified. The MAGE families have their own common characters: They all localized in the X dhromatosomes and expressed specially in malignant tumors and normal testis and placenta tissues. They also have open reading frames and have about 200 homologous sequences of acid residues in their expressed proteins. MAGE antigens act as anti-tumoral immune targets, and have made them a popular focus of immunotherapy researches on gastrointestinal carcinoma and other malignant tumors. Many researchers have made great deals studies utilizing MAGEs as targets antigens and achieved satisfied effects in the experimental therapy.MAGE-4 is a member of MAGE family. It can be found expressing highly in lung squamous cell carcinoma and esophagus squmous cell carcinoma (59% and 74% respectively), and have been used to immunity and biological therapy for cancer. However, there are few studies about its expression and research in gastrointestinal carcinoma which has been reported. The studies have amplified MAGE-4 cDNA from human adenocarcinoma of colon by reverse transcription-polymerase chain reaction and constructed recombinate expressing plasmid pcDNA3.1 + /MAGE-4 correctly. We also constructed MAGE-4 expressing CT26 cell lines. The mice were immunized by pcDNA3.1 +/MAGE-4 and cell mediated immunity and humoral immune reaction can be found activated, and anti-tumor immunity responses have been induced which have conspicuous curative effect.The experiments have been performed in the mice which have been inoculated by MAGE-4 expressing CT26 cells, and the MAGE-4 acted as target antigen while pcDNA3.1/MAGE-4 acted as DNA vaccines. There are significant differences between control group and group which have been immunized by pcDNA3.1 +/ MAGE-4. A new preventing and treating method can be provided by using of MAGE-4, which acts as target antigen. |
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