李斯特菌侵染Vero细胞诱发磷脂酶D活性的变化

ACTIVATION OF HOST PHOSPHOLIPASE D AFTER INVASION OF LISTERIA MONOCYTOGENES INTO VERO CELLS

目的观察在李斯特菌侵染下Vero细胞内磷脂酶D(PLD)活性的变化,为研究PLD在李斯特菌内化侵入Vero细胞过程中的具体激活机制及功能提供一定的理论基础。方法将李斯特菌以不同侵染比(MOI,细菌数:细胞数)及不同侵染时间刺激Vero细胞,应用侵染实验和PLD活性测定方法观察李斯特菌侵染量及Vero细胞内PLD活性的变化。结果当MOI为100:1时李斯特菌侵染量为(99.0±2.6)个,当MOI增加到200:1、400:1时,李斯特菌侵染量分别增加到(150.0±2.6)个和(220.0±1.0)个,并且当MOI值为200:1和400:1时与Vero细胞内基础活性相比,PLD活性均升高近2倍(P<0.05)。当侵染时间为30min时,李斯特菌的侵染量为(102.0±3.0)个,当侵染时间增加到60min和90min时,李斯特菌侵染量分别增加到(185.0±1.7)个和(346.0±4.6)个。李斯特菌侵染15min后,与Vero细胞内PLD基础活性相比升高了大约160%(P<0.05);随着剌激时间的延长,PLD的活性随之升高。结论建立了李斯特菌内化侵入Vero细胞的模型,证实李斯特菌内化侵入Vero细胞对其吞噬的过程中确实伴有PLD的激活。

Objective To study the activity of phospholipase D （PLD） after invasion of Listeria monocytogenes into host cells, so as to provide the theoretical basis for studying the activation mechanism. Methods Vero cells were incubated with Listeria monocytogenes for different multiplicity of infection （MOI, number of bacteria： number of cell） and different time. Then the invasion efficiency of L. monocytogenes into Vero cells were detected and the activity of PLD were assayed. Results The internalized bacteria number increased from 99.0 ± 2.6 to 150.0 ± 2.6, and to 220.0 ± 1.0 respectively when MOI increased from 100： 1 to 200 ： 1, and to 400 ： 1. The activity of PLD was about 2 times higher than basal value when MOI was 200： 1, and 400： 1. The internalized bacteria number was 102.0 ± 3.0 at 30 min of infection time,the number increased with a longer infection time（60 min： 185.0 ± 1.7,90 min： 346.0± 4.6） .The internalization of Listeria monocytogenes into Vero cells was associated with activation of host PLD, the stimulated PLD activity increased with the extention of infection time and was 160% more than basal value at 15 rain. Conclusion With the model of L. monocytogenes-infected Vero cells, we found that the internalization of L. monocytogenes into Vero cells was associated with the activation of host PLD.