Research Center of Swine Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.
Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States.
Vet Microbiol. 2021 Jun;257:109058. doi: 10.1016/j.vetmic.2021.109058. Epub 2021 Mar 26.
Actinobacillus pleuropneumoniae (A.pleuropneumoniae) causes serious economic loss for the swine industry. A high-temperature requirements A (HtrA)-like protease and its homologs have been reported to be involved in protein quality control and expression of important immunoprotective antigens in many pathogens. In this study, we showed that HtrA of A.pleuropneumoniae exhibited both chaperone and proteolytic activities. Moreover, Outer membrane protein P5 (OmpP5) in A.pleuropneumoniae and Heat shock protein 90 (Hsp90) in porcine lung tissues were first discovered and identified as specific proteolytic substrates for rHtrA. The maximum cleavage activity occurs at 50 ℃ in a time-dependent manner. In addition, rHtrA mainly induced IgG 2a subtype of IgG and Th1 (IFN-γ, IL-2) response in a mice model, and promoted a significant proliferation of spleen lymphocytes compare with negative control (P < 0.05). The survival rates of 37.5 % were observed against A.pleuropneumoniae strain. Together, these data demonstrate that rHtrA plays a multi-functional role in A.pleuropneumoniae.
副猪嗜血杆菌（A.pleuropneumoniae）会给养猪业带来严重的经济损失。有报道称，高温需求 A（HtrA）样蛋白酶及其同源物参与了许多病原体中的蛋白质质量控制和重要免疫保护性抗原的表达。在本研究中，我们表明副猪嗜血杆菌的 HtrA 具有分子伴侣和蛋白水解活性。此外，我们首次发现并鉴定了副猪嗜血杆菌中的外膜蛋白 P5（OmpP5）和猪肺组织中的热休克蛋白 90（Hsp90）是 rHtrA 的特异性蛋白水解底物。rHtrA 的最大切割活性在 50℃时随时间呈依赖性增加。此外，rHtrA 在小鼠模型中主要诱导 IgG2a 亚型的 IgG 和 Th1（IFN-γ、IL-2）反应，并与阴性对照相比显著促进了脾淋巴细胞的增殖（P<0.05）。对副猪嗜血杆菌菌株的存活率观察到 37.5%。总之，这些数据表明 rHtrA 在副猪嗜血杆菌中发挥了多功能作用。
