Early after inhalation, Yersinia pestis replicates to high numbers in the airways in the absence of disease symptoms or notable inflammatory responses to cause primary pneumonic plague. The Plasminogen activator protease (Pla) is a critical Y. pestis virulence factor that is important for early bacterial growth in the lung via an unknown mechanism. Here, we define a dual role for Pla in the initial stages of pulmonary infection. We show that Pla functions as an adhesin independent of its proteolytic function to suppresses early neutrophil influx into the lungs, and that Pla enzymatic activity contributes to bacterial resistance to neutrophil-mediated bacterial killing. Our results suggest that the fate of Y. pestis infection of the lung is decided extremely early during infection, and Pla plays a dual role to tilt the balance in favor of the pathogen.

中文翻译：

---

原发性肺鼠疫炎症前阶段纤溶酶原激活物蛋白酶的双重作用。

吸入后早期，鼠疫耶尔森氏菌在没有疾病症状或引起原发性肺鼠疫的显着炎症反应的情况下在气道中大量复制。纤溶酶原激活蛋白酶 (Pla) 是一种关键的鼠疫耶尔森氏菌毒力因子，通过未知机制对肺部早期细菌生长很重要。在这里，我们定义了 Pla 在肺部感染初始阶段的双重作用。我们表明，Pla 作为粘附素发挥作用，与其蛋白水解功能无关，可抑制早期中性粒细胞流入肺部，并且 Pla 酶活性有助于细菌对中性粒细胞介导的细菌杀伤产生抗性。我们的结果表明肺部鼠疫耶尔森氏菌感染的命运在感染过程中极早决定，