表达疟原虫裂殖子表面蛋白1减毒鼠伤寒杆菌的稳定性

Expression and Stability of Fragment of Plasmodium Merozoite Major Surface Protein 1 in Recombinant Attenuated Salmonella Typhimurium

目的检测含恶性疟原虫裂殖子表面蛋白１基因片断的重组减毒鼠伤寒杆菌Ｘ４０６４（ｐＱＥＭ１）的入侵宿主能力，所含质粒的稳定性和再表达能力。方法用含恶性疟原虫裂殖子表面蛋白１第１号基因片段的重组减毒鼠伤寒杆菌Ｘ４０６４（ｐＱＥＭ１）灌胃接种ＢＡＬＢ／ｃ小鼠，用平板培养法、质粒酶切和免疫印迹反应，鉴定从小鼠组织中分离到的该重组菌，测定其表达能力，及在小鼠组织中的消长。结果从小鼠组织中分离到的减毒鼠伤寒杆菌Ｘ４０６４株含有重组的ｐＱＥＭ１质粒；减毒鼠伤寒杆菌Ｘ４０６４（ｐＱＥＭ１）体外表达了恶性疟原虫裂殖子表面蛋白１第１号片断；Ｘ４０６４（ｐＱＥＭ１）在小鼠组织中的消长曲线与Ｘ４０６４的消长曲线基本一致。结论重组ｐＱＥＭ１质粒能稳定地存在于减毒鼠伤寒杆菌Ｘ４０６４株中，不妨碍其入侵宿主细胞，从小鼠组织中分离到的Ｘ４０６４（ｐＱＥＭ１）依然具有表达Ｍ１蛋白的能力。

Objective To determine the invasive ability of recombinant attenuated Salmonella typhimurium X4064(pQEM1)strain containing gene fragment of Plasmodium falciparium merozoite surface protein 1 (MSP1),the stability of its plasmid, and its re expression. Methods BALB/c mice were fed with recombinant attenuated S. typhimurium containing No. 1 gene fragment of P. falciparium MSP1 by gastric tube.Plate incubation,plasmid endonuclease analysis and Western blot were used to identify the recombinant attenuated S. typhimurium strains isolated from mice and the ability of re expression, and its growth were determined in vitro. Results The attenuated strain X4064 of S. typhimurium isolated from mice contained recombinant plasmid pQEM1,no. 1 MSP1 fragment of P. falciparium was expressed in vitro in S. typhimurium X4064(pQEM1)strain,and its growth curve of X4064(pQEM1)strain in mice was basically similar to that of X4064. Conclusion The recombinant plasmid pQEM1 could steadily exist in the X4064 strain of S. typhimurium ,without influence on its invasion into host cells.X4060(pQEM1)strain isolated from infected mice still had the ability to re express M1 protein.