ABSTRACT
OBJECTIVE: To develop a promising approach for tumor immunotherapy with G250 antigen-based DNA vaccine and to investigate its anti-tumor response in mice with renal cell carcinoma. MATERIALS AND METHODS: G250 derived from human, monkey and mouse were prepared by PCR. The heterogeneous chimeric G250 gene was obtained by integrating different gene fragments of three species. Then, the chimeric G250 was inserted into a eukaryotic expression plasmid pVAX1-IRES-GM/B7 to obtain DNA vaccine (named pVAX1-tG250-GM/B7) which could express chimeric G250 antigen and immune adjuvants simultaneously. By transfecting into Cos7 cells, the expression of chimeric G250 antigen was tested using flow cytometry and immunofluorescence assay. The immunological response and protection against tumor were evaluated in vivo. RESULTS: Recombinant plasmid DNA vaccine was constructed successfully through identification of PCR and gene sequencing. The chimeric G250 antigen was well expressed in Cos7 cells. A strong immune response can be detected through ELISPOT and ELISA induced by pVAX1-tG250-GM/B7. The mice vaccinated with pVAX1-tG250-GM/B7, balb/c showed significant inhibition of tumor and a longer time of survival compared with control group. CONCLUSIONS: The experimental results of this study exhibited that the DNA vaccine based on heterogeneous chimeric antigen can produce efficient anti-tumor effect in vivo and they represent a promising strategy for tumor immunotherapy.
