杜莫氏军团菌对上皮细胞A549粘附侵袭和胞内生长能力的研究

摘要

目的 探明杜莫氏军团菌(Legionella dumoffii,L.dumoffii)对上皮细胞A549的粘附、侵袭和胞内生长能力.方法 实验使用菌株为L.dumof fii TEX-KL(ATCC 33343)、L.dumoffii NY23(ATCC 33279)和嗜肺军团菌L.pneumophila philadelphila-1(ATCC 33155).配制1×108菌悬液,将其以100MOI(Muhiplicity of Infection)的比例与肺泡上皮细胞A549相互作用.通过吉曼尼兹染色和菌落计数的方法,测定菌株的粘附、侵袭和胞内生长能力.结果 杜莫氏军团菌L.dumoffii TEX-KL、L.dumoffii NY23和嗜肺军团菌L.pneumophila philadelphila-1三株细菌在体外生长能力和体内对A549细胞的粘附能力方面无明显差别.L.dumoffii TEX-KLL侵袭进入细胞内的菌数是其他两株菌的1 000倍,差异有统计学意义.结论 L.dumoffii TEX KL与L.dumoffii NY23和嗜肺军团菌L.pneumophila philadelphila-1相比,对A549细胞具有更高的侵袭力,因此也具有较高的上度细胞内生长能力.%In this study,the L.dumoffii TEX-KL (ATCC 33343),L.dumoffii NY23 (ATCC 33279) and L.pneumophila philadelphila-1 (ATCC 33155) strains were used to explore the adhesion,invasion and intracellular growth ability in the epithelial cells.Approximately 1× 108 bacteria were pelleted,resuspended,and diluted (1 ∶ 10) in RPMI 1640 tissue culture medium.The bacteria were then added to A549 cells (1 × 105 per well) in 24-well plates to give a multiplicity of infection (MOI) of about 100.The Gimenez staining and colony counting methods were used for the determination of the strain adhesion,invasion and intracellular growth ability.It was found that in vitro growth ability of L.pneumophila philadelphila-1,L.dumoffii TEX-KL and L.dumoffii NY23 strains had no significant difference.For in vivo assay,there was also no significant difference in adhesion ability of these strains.However,the CFU counts of L.dumoffii TEX-KL strain invaded into A549 cells was 1 000 times higher than that of the other two strains.Compared with L.pneumophila philadelphila-1 and L.dumoffii NY23 strains,L.dumoffii TEX-KL strain has higher invasion ability and,therefore,higher intracellular growth ability.