Oral Attenuated Salmonella-mediated Melanoma Dna Vaccine Research

Tumor vaccine delivered by attenuated Salmonella can present the specific tumor antigen to immune cells effectively and stimulate immune response against tumor cells specifically,which provides us a new solution to suppress or even cure cancer. Heat shock protein Hsp70 can present the antigen peptide to antigen presenting cells (APC),activate antigen presenting cells and break the immunological tolerance against tumor-associated antigen(TAA).In this study,we successfully transformed the recombinant vector(pcDNA3.1-Hsp70-Trp2) holding Hsp70 and tyrosinase related protein-2(Trp2) which is a murine melanoma specific antigen,into an attenuated Salmonella typhimurium SL3261.The recombinant attenuated Salmonella typhimurium vaccine was orally administered to mice C57BL/6.After the immunization,murine melanoma specific cytotoxic T lymphocyte(CTL) response and the activity of Natural killer(NK) cell were increased remarkably.The test group showed a cytotoxic T lymphocyte activity of 44.6%(P＜0.01) which is 5 times higher than the PBS control group(8.4%) and a NK cell ratio of 4.0%(P＜0.01) which is 5 times as much as the PBS control group(0.8%).The tolerance induction and protection experiment indicated the oral DNA vaccine delivered by attenuated Salmonella typhimurium had significant inhibitory effect on transplanted B16F10 melanoma tumor growth in mice C57BL/6(P＜0.01).