Brudal Espen, Lampe Elisabeth O, Reubsaet Léon, Roos Norbert, Hegna Ida K, Thrane Ida Marie, Koppang Erling O, Winther-Larsen Hanne C
Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033 Oslo, Norway; Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
Fish Shellfish Immunol. 2015 Jan;42(1):50-7. doi: 10.1016/j.fsi.2014.10.025. Epub 2014 Oct 27.
Infection of fish with the facultative intracellular bacterium Francisella noatunensis remains an unresolved problem for aquaculture industry worldwide as it is difficult to vaccinate against without using live attenuated vaccines. Outer membrane vesicles (OMVs) are biological structures shed by Gram-negative bacteria in response to various environmental stimuli. OMVs have successfully been used to vaccinate against both intracellular and extracellular pathogens, due to an ability to stimulate innate, cell-mediated and humoral immune responses. We show by using atomic force and electron microscopy that the fish pathogenic bacterium F. noatunensis subspecies noatunensis (F.n.n.) shed OMVs both in vitro into culture medium and in vivo in a zebrafish infection model. The main protein constituents of the OMV are IglC, PdpD and PdpA, all known Francisella virulence factors, in addition to the outer membrane protein FopA and the chaperonin GroEL, as analyzed by mass spectrometry. The vesicles, when used as a vaccine, reduced proliferation of the bacterium and protected zebrafish when subsequently challenged with a high dose of F.n.n. without causing adverse effects for the host. Also granulomatous responses were reduced in F.n.n.-challenged zebrafish after OMV vaccination. Taken together, the data support the possible use of OMVs as vaccines against francisellosis in fish.
兼性胞内细菌诺氏弗朗西斯菌（Francisella noatunensis）感染鱼类仍是全球水产养殖业一个尚未解决的问题，因为不使用减毒活疫苗就很难进行疫苗接种。外膜囊泡（OMV）是革兰氏阴性细菌在各种环境刺激下释放的生物结构。由于OMV能够刺激先天免疫、细胞介导免疫和体液免疫反应，已成功用于针对胞内和胞外病原体的疫苗接种。我们通过原子力显微镜和电子显微镜观察发现，鱼类病原菌诺氏弗朗西斯菌诺氏亚种（F.n.n.）在体外向培养基中以及在斑马鱼感染模型体内均能释放OMV。通过质谱分析，OMV的主要蛋白质成分是IglC、PdpD和PdpA，这些都是已知的弗朗西斯菌毒力因子，此外还有外膜蛋白FopA和伴侣蛋白GroEL。这些囊泡用作疫苗时，可减少细菌的增殖，并在随后用高剂量F.n.n.攻击时保护斑马鱼，且不会对宿主造成不良影响。OMV疫苗接种后，受到F.n.n.攻击的斑马鱼的肉芽肿反应也有所减少。综上所述，这些数据支持OMV可能用作鱼类抗弗朗西斯菌病疫苗。
