Rioux S, Dubreuil D, Bégin C, Laferrière C, Martin D, Jacques M
Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Québec, Canada.
Comp Immunol Microbiol Infect Dis. 1997 Jan;20(1):63-74. doi: 10.1016/s0147-9571(96)00022-7.
Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia. The major adhesin of A. pleuropneumoniae has previously been identified as a lipopolysaccharide (LPS), and more recently, we demonstrated that high molecular mass LPS were involved in A. pleuropneumoniae adherence to porcine respiratory tract cells. We postulated that immunization with a LPS-based vaccine may confer a protective immunity. The high molecular mass O-polysaccharides obtained after acid hydrolysis and chromatographic separation were conjugated to bovine serum albumin (BSA) as a protein carrier. Groups of mice were injected twice with the following antigen preparations: whole-cell preparation, outer membrane preparation, O-polysaccharide-BSA conjugate, hydrolyzed LPS and phenol/water extracted LPS. A combination of different adjuvants was also used during these immunization procedures to induce a stronger immunological response to the polysaccharide antigen. Two weeks after the second injection, the mice were challenged intranasally with either homologous A. pleuropneumoniae serotype 1 strain or a serotype 5 strain. The highest survival rate, up to 80%, compared to the control groups (P < 0.05), was recorded when the mice were injected twice with 15 micrograms of carbohydrates of O-polysaccharide-BSA conjugate mixed with the saponin-derived adjuvant Quil A. Survival rates of between 60 and 70%, twice those observed in the control groups immunized with PBS, were recorded in mice injected with the O-polysaccharide-BSA conjugate mixed with other adjuvant preparations such as alhydrogel, peanut oil and Freund's incomplete adjuvant. However, the protection induced by the conjugate antigen preparation was serotype specific, because mice challenged with a serotype 5 strain were killed. Taken together, these results confirm the important role of A. pleuropneumoniae LPS in pathogenesis.
胸膜肺炎放线杆菌是猪胸膜肺炎的病原体。胸膜肺炎放线杆菌的主要黏附素先前已被鉴定为脂多糖（LPS），最近，我们证明高分子量LPS参与胸膜肺炎放线杆菌对猪呼吸道细胞的黏附。我们推测用基于LPS的疫苗进行免疫可能会赋予保护性免疫力。将酸水解和色谱分离后获得的高分子量O-多糖与作为蛋白质载体的牛血清白蛋白（BSA）偶联。给几组小鼠注射以下抗原制剂两次：全细胞制剂、外膜制剂、O-多糖-BSA偶联物、水解LPS和酚/水提取的LPS。在这些免疫程序中还使用了不同佐剂的组合，以诱导对多糖抗原产生更强的免疫反应。第二次注射两周后，用同源的1型胸膜肺炎放线杆菌菌株或5型菌株经鼻攻击小鼠。当给小鼠两次注射15微克与皂素衍生佐剂Quil A混合的O-多糖-BSA偶联物的碳水化合物时，记录到最高存活率，高达80%，与对照组相比（P<0.05）。在用与其他佐剂制剂如氢氧化铝凝胶、花生油和弗氏不完全佐剂混合的O-多糖-BSA偶联物注射的小鼠中，记录到存活率在60%至70%之间，是用PBS免疫的对照组观察到的存活率的两倍。然而，偶联抗原制剂诱导的保护是血清型特异性的，因为用5型菌株攻击的小鼠死亡。综上所述，这些结果证实了胸膜肺炎放线杆菌LPS在发病机制中的重要作用。
