An Oral DNA Vaccine PcDNA3.1+/flk-1_n1-7 Against Colonic Adenocarcinoma Of Mouse

Objective To construct an oral DNA vaccine pcDNA3.1+/flk-1_n1-7 against tumor angiogenesis and investigate the effects and mechanism of the vaccine on tumor development and metastasis in vivo.Methods 1.The recombinant plasmid pcDNA3.1+/ flk-1_n1-7 was transformed into attenuated Salmonella typhimurium SL3261 to develop an oral DNA vaccine against the extracellular domain of flk-1.2.Mice were divided into 3 groups and every group was divided into 3 groups (DNA vaccine group, vector group and saline group) and were orally immunized with SL3261 transformed with therecombinant plasmid, pcDNA3.1 (+), or saline respectively 3 times at 2-week intervals. Then mice in the first group were challenged by subcutaneous (s.c.) injection of colonic adenocarcinoma cells (CT-26) into the right armpit 2 weeks after the last immunization and survival time of the animals was recorded. Mice in the second group were challenged by subcutaneous (s.c.) injection of CT-26 into the right armpit 2 weeks after the last immunization. Flow cytometry (FCM) was used to detect CD3⁺ cells and CD8⁺ T cells before vaccination, after vaccination and after the inoculation of CT-26 cells respectively . Twenty-eight days after tumor cells inoculation, mice were sacrificed and analyzed for tumor...