Quantification of the Adenylate Cyclase Toxin of Bordetella pertussis In Vitro and during Respiratory Infection
Quantification of the Adenylate Cyclase Toxin of Bordetella pertussis In Vitro and during Respiratory Infection
复制标题
DOI：
10.1128/iai.00110-13
复制
发表时间：
2013-05-01
影响因子：
3.1
通讯作者：
Hewlett, Erik L.
中科院分区：
文献类型：
--
作者：
Eby, Joshua C.;Gray, Mary C.;Hewlett, Erik L.
百日咳是由百日咳博德特氏菌呼吸道感染引起的，而分泌的腺苷酸环化酶毒素（ACT）对于细菌建立感染至关重要。尽管在体外对 ACT 细胞毒性机制及其在一定浓度范围内的影响进行了广泛研究，但尚未在体内观察或量化 ACT，因此感染部位的 ACT 浓度未知。最近开发的狒狒感染模型模拟了百日咳的长期咳嗽和传播性，我们假设测量狒狒鼻咽洗液（NPW）中的 ACT 并结合人类和体外数据，可以估计感染期间气道中 ACT 的浓度。在感染高峰期，NPW 含有高达 10(8) CFU/ml 百日咳杆菌和 1 至 5 ng/ml ACT。两名患有百日咳的人类婴儿的鼻吸出物样本中的细菌浓度与狒狒相似，为 12 至 20 ng/ml ACT。当在体外培养类似于 10(8) CFU/ml 的百日咳实验室菌株时，在 60 分钟内检测到 ACT 产量，并在 6 小时内达到类似于 60 ng/ml 的平台。此外，当通过离心使细菌靠近靶细胞时，中毒程度增加了 4 倍。总的来说，这些数据表明，在呼吸道感染过程中，细菌-靶细胞界面处的ACT浓度可超过100ng/ml，为未来ACT和百日咳发病机制的研究提供了参考点。
Whooping cough results from infection of the respiratory tract with Bordetella pertussis, and the secreted adenylate cyclase toxin (ACT) is essential for the bacterium to establish infection. Despite extensive study of the mechanism of ACT cytotoxicity and its effects over a range of concentrations in vitro, ACT has not been observed or quantified in vivo, and thus the concentration of ACT at the site of infection is unknown. The recently developed baboon model of infection mimics the prolonged cough and transmissibility of pertussis, and we hypothesized that measurement of ACT in nasopharyngeal washes (NPW) from baboons, combined with human and in vitro data, would provide an estimate of the ACT concentration in the airway during infection. NPW contained up to similar to 10(8) CFU/ml B. pertussis and 1 to 5 ng/ml ACT at the peak of infection. Nasal aspirate specimens from two human infants with pertussis contained bacterial concentrations similar to those in the baboons, with 12 to 20 ng/ml ACT. When similar to 10(8) CFU/ml of a laboratory strain of B. pertussis was cultured in vitro, ACT production was detected in 60 min and reached a plateau of similar to 60 ng/ml in 6 h. Furthermore, when bacteria were brought into close proximity to target cells by centrifugation, intoxication was increased 4-fold. Collectively, these data suggest that at the bacterium-target cell interface during infection of the respiratory tract, the concentration of ACT can exceed 100 ng/ml, providing a reference point for future studies of ACT and pertussis pathogenesis.