In Vivo Protective Immune Response To Tumor Elicited By Tumor Cell Vaccine

The development of cancer vaccines has been a particularly active area in immunological research fiekL It can be used as active immunothempy method to activate an effective anti-tumor immune response against cancer cells in patients with minimal residual tumor, or as prophylactic vaccine treatment to prevent outgrowth of latent tumor cells in tumor-fire individuals at high risk of developing tnagligancies. With significant advances in understanding this basic immunological phenomena, there are coming kinds of cancer vaccines that can mount more effective immune response. A variety of tumor-associated, tumor-specific antigens and peptides have been identified, and current cancer vaccines strategies ofen use these peptide抋ntigen as immunogens. But these approaches do not lead to great success because generation of an immune response to a single or small number of epitopes is insufficient to mediate total tumor rejection. Compared with this, whole-tumor-cell vaccine, which has stronger immunogenicity, can be easily prepared, cost cheaply, and only need to match one M[JC site, so this kind of vaccine is still a good choice for reseaich and clinical use. Researchers in our labouratoiy have showed that Ehrlich ascites tumor (ET) cell treated with Para appeared promising to act as whole-tumor-cell vaccines with safety and effectiveness. Vaccination protects immunized mice against Ihture challenge with wild-type tumor cells and significantly prolongs mean life span. Prima~y study suggests that both cellular and humorat immune responses might be involved in the protective anti-tumor immune response elicited in immunized mice. Fuithermore, a syngeneic monoclonal antibody (1A3) to ET cell was produced and its target antigen was studied. In order to better understand the mechanism of the immune response and evaluate if 1A3 is involved in this anti-tumor response, in the present study we have investigated the tumor-specific cytotoxicity induced by FT cell vaccine and made attempt to observe therapeutic effect of 1A3 using different schedules of antibody injection. ljlnnor-specific cytotoxicity induced by ET cell vaccine. Using Pam-treated FT cells as ET cell vaccine and treated Sp2/O cells as control vaccine, animal models of tumor vaccination were established. Splenocytes were separated from ET cell vaccine immunized, tumor bearing and control mice respectively. And the cytotoxic rates of these three kinds of splenocytes to ET cells and Sp2/O cells were determined by the 51Cr release assay Using the same method, the cytotoxic rate of splenocytes from control vaccine immunized mice to ET cells was also examined~ The results showed that specific cytotoxic rate of splenocytes from ET cell vaccine immunized mice to ET cells was (42.3 ?3.2)%, significantly higher than that from the other three gmups(P