Age at primary infection with Salmonella enterica serovar Typhimurium in the chicken influences persistence of infection and subsequent immunity to re-challenge
Age at primary infection with Salmonella enterica serovar Typhimurium in the chicken influences persistence of infection and subsequent immunity to re-challenge
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DOI：
10.1016/j.vetimm.2004.04.005
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发表时间：
2004-08-01
影响因子：
1.8
通讯作者：
Smith, AL
中科院分区：
文献类型：
--
作者：
Beal, RK;Wigley, P;Smith, AL
肠道沙门氏菌仍然是人类最重要的食源性病原体之一，通常通过食用受感染的禽肉或禽蛋获得。因此，控制鸡沙门氏菌感染是一个重要的公共卫生问题。链球菌感染肠道血清型鼠伤寒沙门氏菌导致3日龄以上鸡的持续性肠道感染而无临床疾病，并且代表屠宰时的尸体污染源和进入人类食物链。所提供的数据表明，初次接触时的年龄对感染的持续性有深远的影响，而对重新激发的有效免疫力的发展影响较小。沙门氏菌阳性的鸟类百分比在8 - 9周龄之前很高，无论鸟类感染的年龄（1，3或6周）。在3周龄和6周龄感染的鸟产生了更迅速和更高的抗体反应（IgY和IgA）比那些感染在I周龄，但在所有情况下，感染持续了相当长的一段时间，尽管存在高抗体水平。在用S.鼠伤寒沙门氏菌，所有三个先前感染的组有较少的细菌在肠道，脾脏和肝脏相比，年龄匹配的鸟类接受平行的原发性感染。然而，在3周龄和6周龄初次感染的鸡比在较年轻年龄感染的鸡更快地清除感染。有趣的是，在再攻击时，老年引发的鸟类具有更高的特异性T淋巴细胞增殖反应和特异性IgY抗体循环水平。虽然最初在1周龄时感染的鸟类和那些先前未感染的鸟类在再次攻击后产生了更强的抗体反应，但它们从肠道中清除沙门氏菌的速度比表达更强T淋巴细胞反应的老年人更慢。所提供的数据表明，沙门氏菌从肠道的清除是年龄依赖性的，我们认为这与肠道T细胞反应能力的增加有关。沙门氏菌持续存在超过8 - 9周的研究结果，无论暴露时的年龄如何，对肉鸡部门具有影响，并表明需要在整个饲养期间保持无沙门氏菌。此外，再攻击数据表明，在年轻的年龄感染是在产生保护性免疫力比在老鸡有效。在为家禽业的肉鸡部门开发疫苗时，需要考虑保护性免疫力发展的这一特点。(C)2004 Elsevier B.V.保留所有权利。
Salmonella enterica remains one of the most important food-borne pathogens of humans and is often acquired through consumption of infected poultry meat or eggs. Control of Salmonella infections in chicken is therefore an important public health issue. Infection with S. enterica serovar Typhimurium results in a persistent enteric infection without clinical disease in chickens of more than 3 days of age, and represents a source for contamination of carcass at slaughter and entry into the human food chain. Data presented indicate a profound effect of age at initial exposure on the persistence of infection and a lesser effect on the development of effective immunity to re-challenge. The percentage of birds positive for Salmonella was high until 8-9 weeks of age, regardless of the age at which the birds were infected (1, 3 or 6 weeks). The birds infected at 3 and 6 weeks of age produced a more rapid and higher antibody response (IgY and IgA) than those infected at I week of age, but in all cases infection persisted for a considerable period despite the presence of high antibody levels. Following a re-challenge infection with S. Typhimurium, all three previously-infected groups had fewer bacteria in the gut, spleen and liver compared with age-matched birds receiving a parallel primary infection. However, the birds primary infected at 3 and 6 weeks of age cleared infection more rapidly than those infected at a younger age. Interestingly older-primed birds had higher specific T lymphocyte proliferative responses and specific circulating levels of IgY antibody at time of re-challenge. Although birds initially infected at I week of age and those that were previously uninfected produced a stronger antibody response following re-challenge, they were slower to clear Salmonella from the gut than the older-primed groups which expressed a stronger T lymphocyte response. The data presented indicate that clearance of Salmonella from the gut is age-dependent and we propose that this relates to the increased competence of the enteric T cell response. The findings that Salmonella persists beyond 8-9 weeks, irrespective of age at exposure, has implications for the broiler sector and indicates the need to remain Salmonella free throughout the rearing period. Moreover, the re-challenge data demonstrates that infection at a young age is less effective in producing protective immunity than in older chickens. This feature of the development of protective immunity needs to be considered when developing vaccines for the broiler sector of the poultry industry. (C) 2004 Elsevier B.V. All rights reserved.