Laboratory of Food Microbiology and Immunology, Research Center for Animal Hygiene and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido 080-8555, Japan.
Biochem Biophys Res Commun. 2012 May 4;421(2):323-8. doi: 10.1016/j.bbrc.2012.04.007. Epub 2012 Apr 9.
Bacillus anthracis spores germinate to vegetative forms in host cells, and produced fatal toxins. A toxin-targeting prophylaxis blocks the effect of toxin, but may allow to grow vegetative cells which create subsequent toxemia. In this study, we examined protective effect of extractable antigen 1 (EA1), a major S-layer component of B. anthracis, against anthrax. Mice were intranasally immunized with recombinant EA1, followed by a lethal challenge of B. anthracis spores. Mucosal immunization with EA1 resulted in a significant level of anti-EA1 antibodies in feces, saliva and serum. It also delayed the onset of anthrax and remarkably decreased the mortality rate. In addition, the combination of EA1 and protective antigen (PA) protected all immunized mice from a lethal challenge with B. anthracis spores. The numbers of bacteria in tissues of EA1-immunized mice were significantly decreased compared to those in the control and PA alone-immunized mice. Immunity to EA1 might contribute to protection at the early phase of infection, i.e., before massive multiplication and toxin production by vegetative cells. These results suggest that EA1 is a novel candidate for anthrax vaccine and provides a more effective protection when used in combination with PA.
炭疽杆菌孢子在宿主细胞中发芽为营养体形式，并产生致命毒素。毒素靶向预防措施可以阻止毒素的作用，但可能会允许营养体细胞生长，从而导致随后的毒血症。在这项研究中，我们研究了提取抗原 1（EA1）对炭疽病的保护作用。EA1 是炭疽杆菌的主要 S 层成分之一。用重组 EA1 通过鼻腔免疫小鼠，然后用炭疽杆菌孢子进行致命挑战。EA1 的黏膜免疫导致粪便、唾液和血清中抗 EA1 抗体的水平显著升高。它还延迟了炭疽病的发病，并显著降低了死亡率。此外，EA1 和保护性抗原（PA）的组合可保护所有用炭疽杆菌孢子进行致命挑战的免疫小鼠。与对照组和仅用 PA 免疫的小鼠相比，EA1 免疫小鼠组织中的细菌数量明显减少。对 EA1 的免疫可能有助于在感染的早期阶段（即在营养体大量繁殖和产生毒素之前）提供保护。这些结果表明，EA1 是炭疽疫苗的一种新型候选物，与 PA 联合使用时提供更有效的保护。
