Setor de Bacteriologia, Departamento de Medicina Veterinária Preventiva, Universidade Federal de Santa Maria (UFSM), Av. Roraima, 1000, Camobi, Santa Maria, Rio Grande do Sul (RS) CEP 97105-900, Brazil.
School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
Vet Microbiol. 2017 Oct;210:56-63. doi: 10.1016/j.vetmic.2017.08.016.
Moraxella bovis is historically known as the primary agent of infectious bovine keratoconjunctivitis (IBK). However, Moraxella bovoculi and Moraxella ovis are also reported to be involved in the pathogenesis of IBK, therefore, these three species should be included in the development of a new vaccine with a broad-spectrum protection against the disease natural challenge. In this study we investigated the antigenic properties of clinical isolates and reference strains of M. bovis, M. bovoculi and M. ovis using a novel in vitro approach for vaccine evaluation based on two techniques, flow cytometry and western blotting (WB). Here, we demonstrated that rabbit antisera produced against reference M. bovis strain and commercial bacterin showed low number of IgG with capacity to recognize a panel of heterologous strains composed by M. bovoculi and M. ovis. On the other hand, the antisera generated against two clinical isolates of M. ovis (Mov2 and Mov3) presented high cross-reactivity levels against all M. ovis and M. bovis strains evaluated. Similarly, the antisera against Mbv3 (clinical isolate of M. bovoculi) had high levels of IgG associated on the surface of all M. bovoculi strains and most of the M. ovis strains analyzed. The WB analysis demonstrated that Moraxella spp. has multiple immunogenic antigens and most of them are shared between the three species. Based on the cross-reactivity analysis and considering the relative number of IgGs associated on the bacterial surface, we suggest that a multivalent vaccine including Mbv3, Mov2 and Mov3 strains may provide a strong and broad protection against all strains involved in IBK outbreaks.
牛莫拉菌（Moraxella bovis）是传染性牛角膜结膜炎（IBK）的主要病原体。然而，牛莫拉菌（Moraxella bovoculi）和绵羊莫拉菌（Moraxella ovis）也被报道参与 IBK 的发病机制，因此，这三种细菌应该被包括在具有针对疾病自然挑战的广谱保护作用的新型疫苗的开发中。在这项研究中，我们使用基于两种技术（流式细胞术和 Western blot 法）的新型体外疫苗评估方法，研究了临床分离株和参考株牛莫拉菌、牛莫拉菌和绵羊莫拉菌的抗原特性。在这里，我们证明了针对参考牛莫拉菌株和商业菌苗产生的兔抗血清显示出与由牛莫拉菌和绵羊莫拉菌组成的异源株组成的面板的 IgG 数量较少，具有识别能力。另一方面，针对两种绵羊莫拉菌（Mov2 和 Mov3）临床分离株产生的抗血清对所有评估的绵羊莫拉菌和牛莫拉菌菌株表现出高交叉反应性水平。同样，针对 Mbv3（牛莫拉菌的临床分离株）的抗血清具有高水平的 IgG，与所有牛莫拉菌菌株和大多数分析的绵羊莫拉菌菌株表面相关联。WB 分析表明，莫拉菌属具有多种免疫原性抗原，其中大多数抗原在这三个种之间共享。基于交叉反应性分析，并考虑到与细菌表面相关联的 IgG 相对数量，我们建议包括 Mbv3、Mov2 和 Mov3 株的多价疫苗可能会为 IBK 爆发中涉及的所有菌株提供强大而广泛的保护。
