Department of Immunology, Pathophysiology and Veterinary Preventive Medicine, Wrocław University of Environmental and Life Sciences, C.K. Norwida 31 Str, 50-375, Wrocław, Poland.
BMC Vet Res. 2022 Nov 18;18(1):409. doi: 10.1186/s12917-022-03515-x.
Gram-negative bacterial infections are a serious problem in beef and dairy cattle. Bacterial outer membrane proteins (OMPs) play a pivotal role in cellular survival and the host-bacterium interaction. Histophilus somni OMP40 was identified as a porin with homology between its N-terminal amino acid sequence and the sequences of porins of other gram-negative bacteria The aim of this study was to produce recombinant H. somni OMP40 (rOMP40), optimize its production and evaluate its immunogenic properties in calves. The cross-reactivity of anti-rOMP40 antibodies were also checked.
The highest overexpression of rOMP40 was demonstrated by Escherichia coli C41 using the autoinduction process. Double immunization of calves (20 μg rOMP40 per animal) induced a significant increase of anti-rOMP40 antibodies in the IgG (P ≤ 0.01) and IgG (P ≤ 0.01, after first immunization only) subclasses, but not IgM. ELISA revealed increased reactivity of the IgG against surface antigens of E. coli and Pasteurella multocida after the second immunization (P < 0.01). Cross reactivity of anti-rOMP40 antibodies with ~ 40 kDa antigens of most common gram-negative pathogens was shown by Western blotting.
Immunization with H. somni rOMP40 induced a humoral response in cattle with broad cross-reactivity with similar antigens of other species of Pasteurellaceae and Enterobacteriaceae families and the delayed-type hypersensitivity reaction. The obtained results encourage further study to evaluate the protective effect of the produced protein as a subunit vaccine in cattle.
革兰氏阴性菌感染是肉牛和奶牛的严重问题。细菌外膜蛋白（OMP）在细胞存活和宿主-细菌相互作用中起着关键作用。溶血性曼氏杆菌 OMP40 被鉴定为一种孔蛋白，其 N 端氨基酸序列与其同源性序列与其他革兰氏阴性菌的孔蛋白序列之间存在同源性。本研究旨在生产重组 H. somni OMP40（rOMP40），优化其生产并评估其在犊牛中的免疫原性。还检查了抗-rOMP40 抗体的交叉反应性。
使用自动诱导过程，大肠杆菌 C41 表现出 rOMP40 的最高过表达。对犊牛进行两次免疫（每只动物 20μg rOMP40）可显著增加 IgG（P≤0.01）和 IgG（仅首次免疫后 P≤0.01）亚类的抗-rOMP40 抗体，但不能增加 IgM。ELISA 显示，第二次免疫后 IgG 对大肠杆菌和多杀巴斯德氏菌表面抗原的反应性增加（P<0.01）。Western blot 显示抗-rOMP40 抗体与大多数常见革兰氏阴性病原体的~40kDa 抗原具有交叉反应性。
用 H. somni rOMP40 免疫可诱导牛产生广泛的交叉反应性体液反应，与其他巴氏杆菌科和肠杆菌科的相似抗原以及迟发型超敏反应有关。获得的结果鼓励进一步研究评估所产生的蛋白质作为亚单位疫苗在牛中的保护作用。
