卵黄免疫球蛋白（IgY）对断奶仔猪肠产毒性大肠杆菌 K88 黏附的保护作用。
Protective effect of chicken egg yolk immunoglobulins (IgY) against enterotoxigenic Escherichia coli K88 adhesion in weaned piglets.
机构信息
Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Laboratory of Animal Nutrition and Human Health, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China.
Chinese Academy of Science, Institute of Subtropical Agriculture, Research Center for Healthy Breeding of Livestock and Poultry, Hunan Engineering and Research Center of Animal and Poultry Science and Key Laboratory for Agroecological Processes in Subtropical Region, Scientific Observation and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Changsha City, 410125, Hunan, China.
出版信息
BMC Vet Res. 2019 Jul 8;15(1):234. doi: 10.1186/s12917-019-1958-x.
BACKGROUND
Enterotoxigenic Escherichia coli K88 (E. coli K88) are considered as a major cause of diarrhea and death in newly weaned piglets. Oral passive immunization with chicken egg yolk immunoglobulins (IgY) have attracted considerable attention for treatment of gastrointestinal infection due to its high specificity. In this study it was estimated the protective effect of anti-K88 fimbriae IgY against E. coli K88 adhesion to piglet intestinal mucus in vitro and to investigate the potential use of IgY for controlling E. coli-induced diarrhea in weaned piglets in vivo.
RESULTS
E. coli K88 was incubated with IgY for 24 h, and the bacterial growth profiles showed that specific IgY with a concentration higher than 5 mg/mL was observed to significantly inhibit the growth of E. coli K88 compared to nonspecific yolk powder in a liquid medium. Moreover, pretreatment with 50 mg/mL of IgY was found to significantly decrease the adhesion ability of E. coli K88 to porcine jejunal and ileal mucus, further supported by the observations from our immunofluorescence microscopic analysis. In vivo, administration of IgY successfully protected piglets from diarrhea caused by E. coli K88 challenge. Additionally, IgY treatment efficiently alleviated E. coli-induced intestinal inflammation in piglets as the gene expression levels of inflammatory cytokines TNF-α, IL-22, IL-6 and IL-1β in IgY-treated piglets remained unchanged after E. coli K88 infection. Furthermore, IgY significantly prevented E. coli K88 adhering to the jejunal and ileal mucosa of piglets with E. coli infection and significantly decreased E. coli and enterotoxin expression in colonic contents.
CONCLUSION
Outcome of the study demonstrated that IgY against the fimbrial antigen K88 was able to significantly inhibit the growth of E. coli K88, block the binding of E. coli to small intestinal mucus, and protect piglets from E. coli-induced diarrhea. These results indicate that passive immunization with IgY may be useful to prevent bacterial colonization and to control enteric diseases due to E. coli infection. The study has great clinical implication to provide alternative therapy to antibiotics in E coli induced diarrhea.
背景
肠产毒性大肠杆菌 K88（E. coli K88）被认为是新生仔猪腹泻和死亡的主要原因。由于其高度特异性，鸡卵黄免疫球蛋白（IgY）的口服被动免疫已引起人们对治疗胃肠道感染的极大关注。在这项研究中，评估了抗 K88 菌毛 IgY 对体外 E. coli K88 黏附仔猪肠黏液的保护作用，并研究了 IgY 控制断奶仔猪大肠杆菌诱导性腹泻的潜在用途。
结果
将 E. coli K88 与 IgY 孵育 24 小时，细菌生长曲线显示，与非特异性卵黄粉相比，浓度高于 5mg/ml 的特异性 IgY 明显抑制液体培养基中 E. coli K88 的生长。此外，发现用 50mg/ml 的 IgY 预处理可显著降低 E. coli K88 对猪空肠和回肠黏液的黏附能力，免疫荧光显微镜分析进一步支持了这一观察结果。在体内，IgY 的给药成功地保护了仔猪免受 E. coli K88 攻毒引起的腹泻。此外，IgY 治疗可有效缓解仔猪大肠杆菌诱导的肠道炎症，因为 IgY 处理的仔猪在感染 E. coli K88 后，炎症细胞因子 TNF-α、IL-22、IL-6 和 IL-1β 的基因表达水平保持不变。此外，IgY 显著阻止了 E. coli K88 与感染大肠杆菌的仔猪空肠和回肠黏膜的黏附，并显著降低了结肠内容物中大肠杆菌和肠毒素的表达。
结论
研究结果表明，针对菌毛抗原 K88 的 IgY 能够显著抑制 E. coli K88 的生长，阻止 E. coli 与小肠黏液结合，并保护仔猪免受 E. coli 诱导的腹泻。这些结果表明，IgY 的被动免疫可能有助于防止细菌定植，并控制因大肠杆菌感染引起的肠道疾病。该研究为替代抗生素治疗大肠杆菌诱导性腹泻提供了重要的临床意义。
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