表达绿色荧光蛋白的重组减毒鼠伤寒沙门氏菌感染动力学

Dynamics of Recombinant Attenuated Salmonella Typhimurium Expressing Green Fluorescent Protein in Murine Model of Infection

用表达绿色荧光蛋白 ( green fluorescentprotein,GFP)的重组减毒鼠伤寒沙门氏菌 X4 5 5 0 ( p YAGFP)给 BAL B/c小鼠尾静脉注射和口服 ,对小鼠脏器进行细菌计数 ,并用间接 EL ISA法测定血清中抗细菌的抗体。结果表明 ,静脉注射重组菌的小鼠在肝脏、脾脏中重组菌数量有 2个峰值 ,总的趋势是越来越少 ,而血清中抗体效价越来越高 ,可以初步推断 ,肝脏、脾脏中的细菌数量与血清中的抗体水平呈一定的相关性 ;口服重组菌的小鼠 ,在各脏器中重组菌的数量呈现正态分布的变化趋势 ,其中派伊尔结 ( Peyer′s patches,PPs)中细菌数量与血清中的抗体水平呈一定的相关性 ,而脾脏、肝脏及肠系膜淋巴结中细菌数量与血清中的抗体滴度无关。

BALB/c mice were intravenously injected with recombinant attenuated Salmonella typhimurium X4550 expressing GFP,X4550(pYAGFP) and then the spleens and livers were aseptically removed at various time intervals postimmunization.The numbers of bacteria in organs were counted by colony forming units(CFU).Serum samples were obtained from retro orbital sinus and used for the detection of the antibodies against recombinant Salmonella.The results showed the CFU of recombinant Salmonella had two peaks during the observation period,but there was the tendency to diminish.The antibody level in serum was rising in the same period,which showed the immunized mice could produce a relatively high humoral immune responses by intravenous immunization,and it can be inferred that there was correlation between bacteria number and the level of antibodies in serum.BALB/c mice were immunized orally with the same recombinant Salmonella,and spleens,livers,mesenteric lymph nodes,and Peyer′s patches(PPs) were prepared in the same way as mentioned above for the quantification of bacteria.Serum samples were also collected as above.Serum antibodies were tested by indirect ELISA.The results showed the numbers of recombinant bacteria were in Poisson distribution.Interestingly,there was correlation between bacteria CFU in PPs and the anti bacteria antibody level in serum,but there were no such relationship in spleens,livers,mesenteric lymph nodes.All these results define the dynamics of recombinant X4550(pYAGFP) infection in mice model,and give more important information for the development of genetic vaccine based on Salmonella vector.