Matthijs Mieke G R, Ariaans Mark P, Dwars R Marius, van Eck Jo H H, Bouma Annemarie, Stegeman Arjan, Vervelde Lonneke
Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
Vet Immunol Immunopathol. 2009 Jan 15;127(1-2):77-84. doi: 10.1016/j.vetimm.2008.09.016. Epub 2008 Sep 24.
Colibacillosis results from infection with avian pathogenic Escherichia coli bacteria. Healthy broilers are resistant to inhaled E. coli, but previous infection with vaccine or virulent strains of Infectious Bronchitis Virus (IBV) predisposes birds for severe colibacillosis. The aim of this study was to investigate how IBV affects the course of events upon infection with E. coli. Broilers were inoculated with IBV H120 vaccine virus or virulent M41 and challenged 5 days later with E. coli 506. A PBS and E. coli group without previous virus inoculation were included. Sections of trachea, lung and airsacs were stained for CD4, CD8, gammadelta-TCR, alphabeta1-TCR, and for macrophages (KUL-01) and both pathogens. Changes in the mucociliary barrier of trachea, lung and airsacs did not predispose for bacterial superinfection. The disease in the lungs of the E. coli group and both IBV/E. coli groups was similar. Lesions in the airsacs were more pronounced and of longer duration in the IBV/E. coli groups. The immunocytological changes differed substantially between the E. coli group and both IBV/E. coli groups. In trachea, lungs and airsacs the CD4+ and CD8+ populations were significantly larger than in the E. coli and PBS groups. In the lungs and the airsacs the macrophages were more numerous in the IBV/E. coli and the E. coli groups than in the PBS group. The presence of high numbers of T cells and macrophages in IBV infected birds most likely induced an altered immune response, which is responsible for the enhanced clinical signs of colibacillosis.
大肠杆菌病是由禽致病性大肠杆菌感染引起的。健康的肉鸡对吸入的大肠杆菌具有抵抗力，但先前感染疫苗或传染性支气管炎病毒（IBV）的强毒株会使鸡易患严重的大肠杆菌病。本研究的目的是调查IBV如何影响感染大肠杆菌后的病程。给肉鸡接种IBV H120疫苗病毒或强毒株M41，并在5天后用大肠杆菌506进行攻毒。设立了一个未预先接种病毒的PBS和大肠杆菌组作为对照。对气管、肺和气囊切片进行CD4、CD8、γδ-TCR、αβ1-TCR以及巨噬细胞（KUL-01）和两种病原体的染色。气管、肺和气囊的黏液纤毛屏障变化并未使鸡易发生细菌二重感染。大肠杆菌组以及两个IBV/大肠杆菌组鸡的肺部疾病情况相似。在IBV/大肠杆菌组中，气囊中的病变更明显且持续时间更长。大肠杆菌组与两个IBV/大肠杆菌组之间的免疫细胞学变化存在显著差异。在气管、肺和气囊中，CD4+和CD8+细胞群显著大于大肠杆菌组和PBS组。在肺和气囊中，IBV/大肠杆菌组和大肠杆菌组中的巨噬细胞比PBS组更多。在感染IBV的鸡中大量T细胞和巨噬细胞的存在很可能诱导了免疫反应改变，这导致了大肠杆菌病临床症状的加重。
