Campylobacter jejuni is the leading cause of human foodborne enteritis worldwide. Poultry products are regarded as the main source of human campylobacteriosis. Strategies are being developed to reduce colonization of poultry by Campylobacter. The membrane transport protein CjaA was reported to stimulate mucosal immune responses, which can reduce the C. jejuni load in chickens. In this study, oral immunization of broilers with food-grade Lactococcus lactis NZ3900/pNZ8149 carrying the C. jejuni cjaA gene was examined for the ability to reduce colonization of broilers by Campylobacter. The Usp45 signal peptide and the Escherichia coli heat-labile enterotoxin B subunit (LTB) gene fragments were inserted into the upstream and downstream of the cjaA gene for secretory expression and immune enhancement, respectively. The cjaA gene and the fusion cjaA-ltb gene were both expressed in recombinant L. lactis, and the single cjaA gene was secretory expressed in the recombinant strain. Oral administration of two recombinant L. lactis strains expressing the cjaA gene and the fusion cjaA-ltb gene both stimulated specific anti-CjaA serum IgY responses significantly. While the average intestinal sIgA responses in these groups were higher compared with the control groups, they were not significantly different. Chicken challenge experiments showed that the colonization levels of C. jejuni in the groups provided oral immunization with two recombinant L. lactis-delivered CjaA strains were significantly lower than that of the control group at 5 d postinoculation, but there was no significant difference in C. jejuni colonization among all groups at 9 d. These results indicated that recombinant L. lactis with secretory expression of CjaA is a promising live vector vaccine against C. jejuni colonization of chickens. The immunization regimen requires further optimization to ideally stimulate detectable levels of intestinal sIgA to enhance the level of inhibition of C. jejuni colonization.

中文翻译：

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用表达 cjaA 的乳酸乳球菌对鸡进行口服免疫可暂时减少空肠弯曲杆菌的定植。

空肠弯曲杆菌是全世界人类食源性肠炎的主要原因。家禽产品被认为是人类弯曲杆菌病的主要来源。正在制定策略以减少弯曲杆菌对家禽的定殖。据报道，膜转运蛋白 CjaA 可刺激粘膜免疫反应，从而减少鸡的空肠弯曲杆菌负荷。在这项研究中，检查了用带有空肠弯曲杆菌 cjaA基因的食品级乳酸乳球菌NZ3900/pNZ8149对肉鸡进行口服免疫接种以减少弯曲杆菌对肉鸡定殖的能力。Usp45 信号肽和大肠杆菌将不耐热肠毒素 B 亚基 (LTB) 基因片段插入cjaA基因的上游和下游，分别用于分泌表达和免疫增强。的cjaA基因和融合cjaA-LTB基因的重组表达二者乳酸乳球菌，单cjaA基因是分泌在重组菌株中表达。表达cjaA基因和融合cjaA-ltb的两种重组乳酸乳球菌菌株的口服给药基因都显着刺激了特异性抗 CjaA 血清 IgY 反应。虽然这些组的平均肠道 sIgA 反应高于对照组，但它们没有显着差异。鸡挑战实验表明的定殖的水平的空肠弯曲杆菌中的基团具有两个重组提供口服免疫乳酸乳球菌-delivered CjaA株比对照组显着降低了在显著5 d接种后，但有在不显著差异Ç .在第 9 天所有组中空肠的定植。这些结果表明，分泌表达 CjaA 的重组乳酸乳球菌是一种有前景的抗空肠弯曲杆菌的活载体疫苗鸡的殖民化。免疫方案需要进一步优化，以理想地刺激可检测的肠道 sIgA 水平，以提高对空肠弯曲杆菌定植的抑制水平。