[Establishment of mouse melanoma model expressing beta-galactosidase and its application in the research of DNA vaccines against tumor].

We established a mouse melanoma model expressing beta-galactosidase for the study of tumor immunotherapy. The recombinant vector p3gal was constructed by inserting a beta-galactosidase gene into the MCS of plasmid pcDNA3. The vector then transfected the B16 cells. Through selection with 500 microg/ml G418 and in situ X-Gal staining, the melanoma cell line galB16, stably expressing beta-galactosidase was obtained. The melanoma model was successfully established after inoculation in mouse with galB16 cells. In situ X-Gal staining showed that the tumor cells expressed beta-galactosidase in vivo. With the model, we designed animal experiments for mouse tumor immunotherapy. Twenty mice were randomly assigned to four parallel groups. They received i.m. injection with saline, DNA vaccine p3gal (100 microg/mouse), adjuvant CpG 1826 (20 microg/mouse), or p3gal+CpG 1826 respectively. Our result suggested that the DNA vaccine containing beta-galactosidase gene could protect mice against the galB16 tumor challenge. In addition, when combining with the adjuvant CpG 1826, the effect was increased prominently.