Primary infection protects pigs against re-infection with Lawsonia intracellularis in experimental challenge studies
Primary infection protects pigs against re-infection with Lawsonia intracellularis in experimental challenge studies
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DOI：
10.1016/j.vetmic.2010.11.028
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发表时间：
2011-05-05
影响因子：
3.3
通讯作者：
Jungersen, Gregers
中科院分区：
文献类型：
--
作者：
Riber, Ulla;Cordes, Henriette;Jungersen, Gregers
在两项独立的试验中，猪在 56 周龄时被细胞内劳索尼亚菌感染，随后接受抗生素治疗并解决原发感染，然后在 12-13 周龄时重新接种。治疗对照组猪只接受原发感染和抗生素治疗，并作为原发感染抗生素治疗的对照。攻击对照组的猪仅在 12-13 周龄时接受第二次接种，以控制攻击剂量的感染性和该年龄猪对胞内劳森氏菌的敏感性。通过 PCR 监测猪粪便中细胞内乳杆菌的脱落情况，并监测血清中抗体的产生和急性期蛋白的反应。通过免疫组织化学检查死后样本中肠粘膜中胞内乳杆菌抗原的存在。在两项试验中，原发感染猪在攻击接种后均受到保护，免受感染，证据是粪便中没有细胞内乳杆菌脱落，攻击后急性期蛋白浓度没有变化，并且与处理对照猪相比，重新接种猪的肠粘膜中细菌抗原水平较低。相比之下，攻击对照猪在粪便中排出胞内乳杆菌，胞内乳杆菌抗原广泛存在于肠粘膜的所有层中，并且在实验感染后在血清中产生显着的急性期蛋白反应。检测到对胞内乳杆菌感染的急性期蛋白反应表现为从感染后第 6 天开始血清 C 反应蛋白和触珠蛋白浓度升高，并且在 5-6 周龄和 12-13 周龄接种后 2-3 周通常可以看到触珠蛋白血清浓度升高。 总之，与年龄匹配对照中的感染发展相比，在重新接种的猪中发现了针对胞内乳杆菌感染的实质性保护作用猪。急性期蛋白反应反映了在二次攻击时观察到的针对胞内乳杆菌感染的保护作用，以及随着年龄的增长而增加的对感染的抵抗力。 (C) 2010 Elsevier B.V. 保留所有权利。
In two separate trials pigs were experimentally infected with Lawsonia intracellularis at 56 weeks of age followed by antibiotic treatment and resolution of the primary infection and then re-inoculated at 12-13 weeks of age. A treatment-control group of pigs received the primary infection and antibiotic treatment only, and served as control for the antibiotic treatment of the primary infection. A challenge-control group of pigs received the second inoculation dose only at 12-13 weeks of age to control infectivity of the challenge-dose and susceptibility of pigs to L intracellularis at this age. Pigs were monitored for shedding of L intracellularis in faeces by PCR, and for the development of antibodies and responses of acute phase proteins in serum. The presence of L intracellularis antigen in the intestinal mucosa was examined in post mortem samples by immunohistochemistry.In both trials primary infected pigs were protected from infection after challenge inoculation as evidenced by absence of faecal shedding of L intracellularis, lack of changes in acute phase protein concentrations after challenge and with low levels of bacterial antigen in the intestinal mucosa of re-inoculated pigs comparable to that of the treatment-control pigs. In contrast, challenge-control pigs shed L. intracellularis in faeces, had L. intracellularis antigen extensively present within all layers of the intestinal mucosa and developed a significant acute phase protein response in serum after the experimental infection. The acute phase protein response to L. intracellularis infection was detected as an increased rise in the serum concentrations of C-reactive protein and haptoglobin from day-6 post infection, and increased serum concentrations of haptoglobin were generally seen 2-3 weeks after inoculation both at 5-6 and 12-13 weeks of age.In conclusion substantial protection against L. intracellularis infection was found in the re-inoculated pigs in contrast to the development of infection in age-matched control pigs. The acute phase protein responses reflected both the observed protection against L. intracellularis infection upon secondary challenge and that increased resistance to the infection develops with age. (C) 2010 Elsevier B.V. All rights reserved.