猪链球菌在呼吸道上皮细胞中感染特性的研究

Infection characteristics of Streptococcus suis on the respiratory epithelial cells

为研究猪链球菌(S.suis)在呼吸道上皮细胞中的感染特性,本研究采用猪肺组织精细切片(PCLS)和猪呼吸道上皮细胞气-液培养体系(ALI)两种猪呼吸系统培养体系,研究S.suis对猪呼吸系统上皮细胞的感染特性。利用S.suis 10型感染PCLS 24 h后,通过间接免疫荧光试验(IFA)检测,结果显示在支气管管腔上皮细胞表面检测到大量S.suis,表明S.suis能够定植于PCLS,同时表明该体系可用于S.suis在肺组织中感染特性的研究。上皮细胞经培养后划伤部分表面,利用ALI培养体系检测S.suis对支气管上皮细胞的感染特性,通过IFA检测结果显示S.suis更易定植于受损伤的上皮细胞创面周围,表明支气管上皮细胞损伤能够促进S.suis吸附在受伤的细胞部位。进一步通过扫描电镜检测S.suis在ALI培养体系中的吸附特性,可更直观的发现S.suis主要吸附在纤毛细胞的纤毛上。本研究首次利用PCLS和ALI两种培养体系鉴定了S.suis可以感染支气管上皮,而且其主要吸附在支气管上皮细胞的纤毛上,细胞损伤会促进S.suis的吸附,该结果为进一步研究S.suis在宿主呼吸系统中的感染机制提供了科学工具和参考依据。

In order to analyze the infection characteristics of S.suis on epithelial cells of respiratory system,two swine respiratory culture systems have been established,including porcine precision-cut lung slices(PCLS)and porcine respiratory epithelial cells air-liquid interface culture system(ALI).First of all,significant amount of S.suis attached to the luminal surface of bronchus at 24 hpi,which detected by indirect immunofluorescence assay(IFA),when PCLS were inoculated by S.suis.These results suggest that S.suis adhere to PCLS culture system and the PCLS is able to be used as a model to analyze the infection characteristics of S.suis in lung tissue.Furthermore,the infection characteristics of S.suis on bronchial epithelial cells were analyzed by ALI culture system.The results showed that S.suis was able to adhere to ALI culture system and mainly attached to the cilia of ciliated cells,and injury of bronchial epithelium promoted the adherence of S.suis around injured tissue.Besides,the adherence characteristics of S.suis to ALI culture were detected by scanning electron microscopy,which clearly showed that S.suis was mainly adhere to the cilia of epithelial ciliated cells.In summary,we successfully identified that S.suis primarily attached to the cilia of bronchial epithelium ciliated cells in the PCLS and ALI culture systems,and the adherence were enhanced on injured epithelium.This study provides scientific models and theoretical foundation for analyzing the infection characteristics of S.suis on respiratory system.