Generation And Study Of PR39 Transgenic Mice

Antimicrobial peptides(AMPs) play an important role in animal's innate immune system.AMPs have broad spectrum anti-pathogenic micoorganisms and anti-cancer effects. They are rarely to induce drug resistance for micorganisms and easy to be degraded in animal body. Therefore AMPs are widely considered as the ideal alternative for antibiotics. AMPs have been used as feed additives in animal husbandy. However, the activity of AMPs is easy to be decreased during the production, storage and shipping of AMPs. Furthermore, addition of AMPs to feed incrases the cost of farm animal production.The above problems can be solved by transgenic expression of AMPs in animals. In this study, a vector called p CMS-EGFP-PR39 was constructed. This vector carries a pig-derived AMP gene called PR39(proline- arginine-rich 39- amino acid peptide). This vector can express anti-bacterial PR39 in cultured 293 cells. Eight transgenic mice were produced by pronuclear microinjection of linearized p CMS-EGFP-PR39 plasmid into mouse fertilizated eggs. The expression and inheritance of PR39 transgene in transgenic mice were analyzed. The anti-bacterial ability was compared between transgenic mice and their wild-type littermates following artificial infection of swine Actinobacillus pleuropneumonia(APP). The main results are as follws.(1)The PR39 transgene was expressed in various tissues of transgenic mice and stably passed to next generation. Transgenic mice have a significantly higher gowth rate than their wild-type littermates.(2)During 5-24 h post infection of APP, the mortality rate of transgenic mice was significantly lower than that of their wild-type littermates.(3)At 5h post infection of APP, live transgenic mice carry significantly lower number of APP in various tissues than that of their live wild-type littermates, and live transgenic mice showed minor histopathological symptoms than that of their live wild-type littermates. This suggests that transgenic mice have increased anti-bacteiral ability.(4)During 5-17 h post infection of APP, dead transgenic mice carry significantly higher number of APP in various tissues than that of their dead wild-type littermates, and dead transgenic mice showed minor histopathological symptoms than that of their dead wild-type littermates. This implies that transgenic mice have enhanced tolerance of bacterial infection and hence a higher dose of APP was needed to kill them. The above results indicated that transgenic expression of PR39 in transgenic mice enhance their resistance to bacterial infection. This study provided scienfic information for future generation of bacterial-resistant transgenic pigs expressing PR39.