Evaluation of the adjuvant effect of Salmonella-based Escherichia coli heat-labile toxin B subunits on the efficacy of a live Salmonella-delivered avian pathogenic Escherichia coli vaccine
Evaluation of the adjuvant effect of Salmonella-based Escherichia coli heat-labile toxin B subunits on the efficacy of a live Salmonella-delivered avian pathogenic Escherichia coli vaccine
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DOI：
10.1080/03079457.2013.811466
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发表时间：
2013-08-01
期刊：
影响因子：
2.8
通讯作者：
Lee, John Hwa
中科院分区：
文献类型：
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作者：
Chaudhari, Atul A.;Lee, John Hwa
本研究评价了表达不耐热性大肠杆菌B亚单位(LTB)毒素的减毒活沙门氏菌对禽致病性大肠杆菌(APEC)疫苗免疫效果的影响。将含有LTB基因的asd(+)(天冬氨酸半醛脱氢酶)表达载体pMMP906导入缺失lon、cpxR和asd基因的鼠伤寒沙门氏菌中，获得佐剂菌株。本研究使用了重组沙门氏菌活疫苗候选疫苗。这些鸟被分成三组：A组，未接种疫苗的对照组；B组，仅用候选疫苗免疫；以及C组，用候选疫苗和LTB株免疫。对这些鸟的免疫反应进行了测量，并在21日龄时用APEC毒株攻击这些鸟。C组血浆免疫球蛋白和肠道免疫球蛋白A水平显著高于其他组，淋巴细胞增殖反应显著高于其他组。用APEC强毒株攻击后，C组表现出有效的保护作用，而B组则没有。我们还试图优化佐剂的有效剂量。将候选疫苗与LTB菌株的1x10(7)或1x10(8)集落形成单位一起免疫这些禽类，随后在3周龄时进行攻击。LTB株的1×10(7)集落形成单位表现出较强的佐剂效应，血清免疫球蛋白、肠道免疫球蛋白A水平升高，淋巴细胞增殖反应增强，对攻击具有较强的保护作用。总体而言，LTB菌株提高了沙门氏菌提供的APEC疫苗的效力，表明APEC疫苗与LTB菌株一起接种似乎提高了预防肉鸡大肠杆菌病的效力。
The present study evaluated the adjuvant effect of live attenuated salmonella organisms expressing the heat-labile toxin of Escherichia coli B subunit (LTB) on the efficacy of an avian pathogenic Escherichia coli (APEC) vaccine. The Asd(+) (aspartate semialdehyde dehydrogenase) plasmid pMMP906 containing the LTB gene was introduced into a Salmonella enterica Typhimurium strain lacking the lon, cpxR and asd genes to generate the adjuvant strain. Live recombinant Salmonella-delivered APEC vaccine candidates were used for this study. The birds were divided into three groups: group A, non-vaccinated controls; group B, immunized with vaccine candidates only; and group C, immunized with vaccine candidates and the LTB strain. The immune responses were measured and the birds were challenged at 21 days of age with a virulent APEC strain. Group C showed a significant increase in plasma IgG and intestinal IgA levels and a significantly higher lymphocyte proliferation response compared with the other groups. Upon challenge with the virulent APEC strain, group C showed effective protection whereas group B did not. We also attempted to optimize the effective dose of the adjuvant. The birds were immunized with the vaccine candidates together with 1x10(7) or 1x10(8) colony-forming units of the LTB strain and were subsequently challenged at 3 weeks of age. The 1x10(7) colony-forming units of the LTB strain showed a greater adjuvant effect with increased levels of serum IgG, intestinal IgA and a potent lymphocyte proliferation response, and yielded higher protection against challenge. Overall, the LTB strain increased the efficacy of the Salmonella -delivered APEC vaccine, indicating that vaccination for APEC along with the LTB strain appears to increase the efficacy for protection against colibacillosis in broiler chickens.