Prophylaxis of tumor through oral administration of IL-12 GM-CSF gene carried by live attenuated salmonella

A live attenuated AraA(-) autotrophic mutant of Salmonella typhimurium (SL3 261) was used as carrier for eukaryotic expression vectors EGFPN1, pCMVmIL- 12, pCMVhIL-12, pCMVmGM-CSF and pCMVhGM-CSF and was administered orally to BALB/c and C57BL/6 mice. After 6 weeks, these mice were challenged with 4T1 and Lewis tumor cells respectively. GFP expression and gene integration co uld be detected in mice's livers, spleens, intestines, kidneys and tumors. The serum level of cytokines increased significantly in treated mice, so di d the ratio of CD8+/CD4+, which resulted in the tumor regression and prolon gation of the survival time of those mice. These researches laid an experim ental foundation for the tumor gene therapy using live attenuated salmonell a.