Vilte D A, Larzábal M, Mayr U B, Garbaccio S, Gammella M, Rabinovitz B C, Delgado F, Meikle V, Cantet R J C, Lubitz P, Lubitz W, Cataldi A, Mercado E C
Instituto de Patobiología, Instituto Nacional de Tecnología Agropecuaria (INTA), Nicolás Repetto y De los Reseros, 1686 Hurlingham, Argentina.
Vet Immunol Immunopathol. 2012 Apr 15;146(2):169-76. doi: 10.1016/j.vetimm.2012.03.002. Epub 2012 Mar 10.
Cattle are the main reservoir of enterohemorrhagic Escherichia coli O157:H7, a bacterium that, in humans, causes hemorrhagic colitis and hemolytic uremic syndrome (HUS), a life-threatening disease, especially in children and older people. Therefore, the development of vaccines preventing colonization of cattle by E. coli O157:H7 could be a main tool for an HUS control program. In the present study, we evaluated bacterial ghosts (BGs) of E. coli O157:H7 as an experimental vaccine against this pathogen. BGs are empty envelopes of Gram-negative bacteria, which retain the morphological surface make-up of their living counterparts and are produced by controlled expression of the cloned protein E, which causes loss of all the cytoplasm content. In this work, E. coli O157:H7 BGs were used for subcutaneous immunization of calves. The vaccinated animals elicited significant levels of BG-specific IgG but not IgA antibodies in serum. Low levels of IgA and IgG antibodies against BGs were detected in saliva from vaccinated animals. Following oral challenge with E. coli O157:H7, a significant reduction in both the duration and total bacterial shedding was observed in vaccinated calves compared to the nonimmunized group. We demonstrated that systemic vaccination with E. coli O157 BGs provides protection in a bovine experimental model. Further research is needed to reach a higher mucosal immune response leading to an optimal vaccine.
牛是肠出血性大肠杆菌O157:H7的主要宿主，这种细菌在人类中会引发出血性结肠炎和溶血尿毒综合征（HUS），这是一种危及生命的疾病，在儿童和老年人中尤为严重。因此，开发能够预防牛被O157:H7大肠杆菌定植的疫苗可能是控制HUS项目的主要手段。在本研究中，我们评估了O157:H7大肠杆菌的细菌幽灵（BGs）作为针对这种病原体的实验性疫苗。BGs是革兰氏阴性菌的空包膜，保留了其活体细胞的形态表面结构，由克隆的E蛋白的可控表达产生，E蛋白会导致所有细胞质内容物流失。在这项工作中，O157:H7大肠杆菌BGs被用于对小牛进行皮下免疫。接种疫苗的动物血清中产生了显著水平的BG特异性IgG抗体，但未产生IgA抗体。在接种疫苗动物的唾液中检测到低水平的抗BGs IgA和IgG抗体。在用O157:H7大肠杆菌进行口服攻毒后，与未免疫组相比，接种疫苗的小牛在排菌持续时间和总排菌量上均有显著减少。我们证明，用O157大肠杆菌BGs进行全身接种在牛实验模型中提供了保护作用。需要进一步研究以获得更高的黏膜免疫反应，从而研发出最佳疫苗。
