NetB, a new toxin that is associated with avian necrotic enteritis caused by Clostridium perfringens.
NetB, a new toxin that is associated with avian necrotic enteritis caused by Clostridium perfringens.
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DOI：
10.1371/journal.ppat.0040026
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发表时间：
2008-02-08
期刊：
影响因子：
6.7
通讯作者：
Moore RJ
中科院分区：
文献类型：
--
作者：
Keyburn AL;Boyce JD;Vaz P;Bannam TL;Ford ME;Parker D;Di Rubbo A;Rood JI;Moore RJ
30多年来，一种称为α毒素的磷脂酶C被认为是产气荚膜梭菌引起的坏死性肠炎的关键毒力因子。然而，使用基因敲除突变体，我们最近表明，α-毒素是不是必不可少的发病机制。我们现在已经发现了一个关键的毒力决定因素。从一株C.从患有坏死性肠炎（NE）的鸡中分离的产气荚膜杆菌菌株。该毒素与包括C.产气荚膜杆菌（38%同一性）和来自金黄色葡萄球菌的α-毒素（31%同一性）。NetB仅在C中被识别。从患有NE的鸡分离的A型产气荚膜杆菌菌株。纯化的天然NetB和重组NetB显示对鸡来航雄性肝癌细胞系LMH的细胞毒活性，诱导细胞变圆和溶解。为了确定NetB在NE中的作用，将一株强毒C.通过同源重组构建产气荚膜杆菌鸡分离株，并在鸡疾病模型中评估其毒力。netB突变体不能引起疾病，而野生型亲本菌株和与野生型netB基因互补的netB突变体引起显著水平的NE。这些数据明确地表明，在该分离株中，功能性NetB毒素对于C.产气荚膜杆菌引起鸡的NE。这种新毒素是第一个确定的毒力因子被确定在禽C。产气荚膜杆菌菌株能够引起NE。此外，netB突变体是第一个从引起NE的C.产气荚膜杆菌;因此，它具有相当大的疫苗潜力。 产气荚膜梭菌可引起人类气性坏疽和食物中毒，并引起动物的几种肠毒血症疾病，包括禽坏死性肠炎。这种疾病影响到全世界所有的养鸡国家，对商业养鸡业是一个相当大的负担。直到最近，α毒素被认为是坏死性肠炎的主要毒力因子。然而，通过使用α-毒素无效突变体，已经证明该毒素不是疾病所必需的。本文详细介绍了一种新的毒素，NetB的鉴定和表征，并提供证据表明，该蛋白质是一个必不可少的因素，导致鸡坏死性肠炎。NetB与C的β毒素具有有限的蛋白质序列同一性。产气荚膜杆菌，其引起人和动物小肠的粘膜坏死。我们证明了NetB无效突变体不再引起鸡的疾病，而野生型和突变体与野生型netB基因互补引起显著水平的坏死性肠炎。这种重要毒素的鉴定推进了我们对该病发病机制的理解，并为开发针对家禽坏死性肠炎的新型疫苗提供了重要机会。
For over 30 years a phospholipase C enzyme called alpha-toxin was thought to be the key virulence factor in necrotic enteritis caused by Clostridium perfringens. However, using a gene knockout mutant we have recently shown that alpha-toxin is not essential for pathogenesis. We have now discovered a key virulence determinant. A novel toxin (NetB) was identified in a C. perfringens strain isolated from a chicken suffering from necrotic enteritis (NE). The toxin displayed limited amino acid sequence similarity to several pore forming toxins including beta-toxin from C. perfringens (38% identity) and alpha-toxin from Staphylococcus aureus (31% identity). NetB was only identified in C. perfringens type A strains isolated from chickens suffering NE. Both purified native NetB and recombinant NetB displayed cytotoxic activity against the chicken leghorn male hepatoma cell line LMH; inducing cell rounding and lysis. To determine the role of NetB in NE a netB mutant of a virulent C. perfringens chicken isolate was constructed by homologous recombination, and its virulence assessed in a chicken disease model. The netB mutant was unable to cause disease whereas the wild-type parent strain and the netB mutant complemented with a wild-type netB gene caused significant levels of NE. These data show unequivocally that in this isolate a functional NetB toxin is critical for the ability of C. perfringens to cause NE in chickens. This novel toxin is the first definitive virulence factor to be identified in avian C. perfringens strains capable of causing NE. Furthermore, the netB mutant is the first rationally attenuated strain obtained in an NE-causing isolate of C. perfringens; as such it has considerable vaccine potential. Clostridium perfringens can cause gas gangrene and food poisoning in humans and causes several enterotoxemic diseases in animals including avian necrotic enteritis. This disease affects all chicken producing countries worldwide and is a considerable burden on the commercial chicken production industry. Until recently alpha-toxin was thought to be the major virulence factor involved in necrotic enteritis. However, by using an alpha-toxin null mutant it has been demonstrated that this toxin is not essential for disease. This paper details the identification and characterisation of a novel toxin, NetB, and provides evidence that the protein is an essential factor in causing necrotic enteritis in chickens. NetB has limited protein sequence identity to the beta-toxin of C. perfringens, which causes mucosal necrosis of the small intestine in humans and animals. We demonstrate that NetB null mutants can no longer cause disease in chickens, whereas both the wild-type and mutant complemented with a wild-type netB gene caused significant levels of necrotic enteritis. The identification of this important toxin advances our understanding of the pathogenesis of the disease and opens significant opportunities for the development of novel vaccines against necrotic enteritis in poultry.
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影响因子：
1.4
作者：
HELMBOLDT, CF;BRYANT, ES
通讯作者：
BRYANT, ES
DOI：
10.1016/s0925-4439(99)00026-5
发表时间：
1999-05-31
影响因子：
6.2
作者：
Nagahama, M;Kihara, A;Sakurai, J
通讯作者：
Sakurai, J
DOI：
10.1073/pnas.0335853100
发表时间：
2003-02-04
影响因子：
11.1
作者：
Brüggemann, H;Bäumer, S;Gottschalk, G
通讯作者：
Gottschalk, G
影响因子：
3.6
作者：
Fisher, DJ;Miyamoto, K;McClane, BA
通讯作者：
McClane, BA
影响因子：
3.6
作者：
LYRISTIS, M;BRYANT, AE;ROOD, JI
通讯作者：
ROOD, JI