Theuß Tobias, Ueberham Elke, Lehmann Jörg, Lindner Thomas, Springer Sven
IDT Biologika GmbH, Business Unit Animal Health, Research and Development, Am Pharmapark, 06861, Dessau-Rosslau, Germany.
Fraunhofer Institute for Cell Therapy and Immunology, Perlickstraße 1, 04103, Leipzig, Germany.
BMC Vet Res. 2017 Nov 17;13(1):343. doi: 10.1186/s12917-017-1271-5.
Monophasic Salmonella Typhimurium (mSTM) strains account for up to 8.6% of all human Salmonellosis cases. They have an increasing prevalence during recent years and several human cases with hospitalisation were reported. These strains are often isolated from pigs and pork - one primary source of human infection. A Salmonella Typhimurium (STM) live vaccine has been proven successful in controlling of STM infections in pigs for many years. The aim of this study was to test the immunogenicity of the vaccine in weaners during oral challenge with a virulent mSTM strain and to examine the kinetics of STM-specific IgA, IgM and IgG antibodies induced by vaccination and infection.
Despite clinical signs being present in both groups, the vaccination led to a significant reduction of diarrhoea, overall clinical symptoms and a milder elevation of the body temperature. Necropsy revealed fewer pathological lesions in the gastrointestinal tract of vaccinated compared to control animals. Moreover, in the ileal and caecal mucosa and in the ileocaecal lymph nodes the challenge strain burden was significantly reduced by vaccination. Significant differences in the antibody responses of both groups were present during the vaccination period and after infection. In vaccinated animals Salmonella-specific IgA and IgG antibody levels increased significantly after vaccination and were even more pronounced in response to challenge. In contrast, similarly low levels of IgM antibodies were detected during the vaccination period in both vaccinated and non-vaccinated animals. However, after challenge IgM antibody levels increased significantly in control pigs while neither IgA nor IgG antibodies were detectable.
The data demonstrate that mSTM can evoke clinical signs in weaners. Due to the vaccination their incidence and magnitude were significantly milder. Vaccination also led to a significantly reduced challenge strain burden in the intestine and the lymph nodes which is comparable to previous studies using the same vaccine in a challenge with biphasic STM. Therefore, it is concluded that this vaccine induces immunity against monophasic and biphasic STM strains. Furthermore, the results of antibody profiles in response to vaccination and infection provide additional evidence for humoral immune mechanisms triggered during Salmonella infection or vaccination.
单相鼠伤寒沙门氏菌（mSTM）菌株占所有人类沙门氏菌病病例的比例高达8.6%。近年来其流行率不断上升，并有多例人类住院病例报告。这些菌株常从猪和猪肉中分离出来，而猪和猪肉是人类感染的主要来源之一。一种鼠伤寒沙门氏菌（STM）活疫苗多年来已被证明在控制猪的STM感染方面是成功的。本研究的目的是在断奶仔猪经强毒mSTM菌株口服攻毒期间测试该疫苗的免疫原性，并研究疫苗接种和感染诱导的STM特异性IgA、IgM和IgG抗体的动力学。
尽管两组均出现临床症状，但疫苗接种导致腹泻、总体临床症状显著减轻，体温升高幅度较小。尸检显示，与对照动物相比，接种疫苗动物的胃肠道病理损伤较少。此外，在回肠和盲肠黏膜以及回盲部淋巴结中，疫苗接种显著降低了攻毒菌株的负荷。在疫苗接种期间和感染后，两组的抗体反应存在显著差异。在接种疫苗的动物中，沙门氏菌特异性IgA和IgG抗体水平在接种疫苗后显著升高，在攻毒后更为明显。相比之下，在疫苗接种期间，接种疫苗和未接种疫苗的动物中检测到的IgM抗体水平同样较低。然而，攻毒后，对照猪的IgM抗体水平显著升高，而未检测到IgA和IgG抗体。
数据表明mSTM可在断奶仔猪中引发临床症状。由于接种疫苗，其发病率和严重程度显著减轻。疫苗接种还导致肠道和淋巴结中攻毒菌株的负荷显著降低，这与之前使用同一疫苗对双相STM进行攻毒的研究结果相当。因此，得出结论，该疫苗可诱导针对单相和双相STM菌株的免疫力。此外，接种疫苗和感染后的抗体谱结果为沙门氏菌感染或疫苗接种期间触发的体液免疫机制提供了额外证据。
