| The prognosis for patients with primary malignant gastric carcinoma remains poor, in spite of a variety of different forms of treatment. Surgery, radiotherapy, and chemotherapy or combined therapeutic procedures rarely succeed in curing the disease. There are several factors affected the treatment of gastric carcinoma , one of which is these patients with a lower immune response. In order to increase host immune function and inhibit tumor growth, many kinds of immunotherapy have been tried, but the conventional immunotherapy against gastric carcinoma showed little effects. From 1990, a variety of gene therapy, such as suicide gene therapy, tumor suppress gene therapy and antisense gene therapy, have been explored for gastric carcinoma. But the relative clinical research is still in the air. The main obstacles are that the traditional scheme of gene therapy introduces the methods of non-replicative virus or physical chemistry. It is difficult to overcome the Low gene transferring rate and expression capacity, along with the characteristic of poor-target to tumor cells that are the reasons we haven't yet cured the malignant tumor by these methods. Lately a new kind of oncolytic replicative virus has been discovered for its surprising effect on tumor therapy. Because of some discrepancies between the tumor and the normal cells, the virus can specially proliferate in the tumor cells, but not in the normal cells and induce the cells to death., so that it can specially kill the tumor cells. Interleukin-12 (IL-12) is a cytokine with many immunobiological activities which is disulfide-linked heterodimer molecule produced predominantly by professional antigen presenting cells. It not only activates CTL and NK cells,but also promotes the induction of sundry biological effects with significant relevance to anticancer immunity, such as enhancement of T (H) 1 helper response, an in vivo antiangiogenic effect, and induction of adhesion molecules that assist in lymphocyte homing to sites of tumor growth. Also Interleukin-12 (IL-12) can not only directly induce and enhance the activity of lymphokine activated killer (LAK) cells, butalso stimulates IFN-gamma production in both T cells and NK cells. Therefore we constructed a new vector that was inserted an anti-cancer gene (mIL-12) into the genome of the adenovirus. So the anti-cancer gene can be specially and highly expressed in the tumor cells by the viruses, characteristically proliferating in the tumor cells. The new scheme that can exploit the virtues of virus therapy and gene therapy is named as gene-virus therapeutics. It overcomes the disadvantages of traditional gene therapy, such as low transferring rate, low expression capacity and poor-target tropism. In our study , we investigated the anti-tumor effect of carrying interleukin-12 with the replication adenovirus compared with non-replicative adenovirus, and the influence of the tumor-specific replication-competent adenovirus vector system carrying Interleukin-12 gene on the chemothercutic agent.1．The preparation and constructions of the replication-competent and non-replication-competent adenovirus-mediated transfer of Interleukin-12 gene.CNHK200-mIL-12 and Ad-mIL-12 adenovirus vectors were constructed by means of recombination technique. The correct sequences were identified by the method of PCR. CNHK200-mIL-12 and Ad-mIL-12 were transfected into the 293 cell and amplified, then was purified by cesium chloride density purification, titrated by TCID50 method and then stored at -80℃ for usage. Finally the titer of CNHK200-mIL-12 and Ad-mIL-12 were the same 1010 PUF/ml. The biological activities of mIL-12 produced by CNHK200-mIL-12 and Ad-mIL-12 were compared with standard sample. There was no significant difference between them.2．Effects of replication-competent and non-replication adenovirus-mediated transfer of Interleukin-12 gene in vitro.By means of the methods of fluorescence microscopy and fluorescence-activated cell sorting (FACS) and electron microscopy, the outcome showed that repli...
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