Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria 3010, Australia.
Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria 3010, Australia.
Vaccine. 2018 Apr 25;36(18):2487-2493. doi: 10.1016/j.vaccine.2018.02.117. Epub 2018 Mar 26.
Mycoplasma gallisepticum (MG) is an important pathogen of poultry worldwide that causes chronic respiratory disease (CRD) in chickens and infectious sinusitis in turkeys. Vaxsafe MG (strain ts-11) is a live attenuated temperature sensitive vaccine that has been proven to be effective in controlling CRD in chickens, but it is not efficacious in turkeys. The gapA gene, which encodes a mature cytadhesin protein with a molecular weight of approximately 105 kDa, is not expressed in strain ts-11 because a 20 base pair reiterated sequence introduces a frame shift and causes premature truncation of the translated peptide. A GapA positive clone, MG ts-304, isolated from strain ts-11 has been shown to have enhanced efficacy in chickens. Here we describe studies we conducted to assess the safety and efficacy of the MG ts-304 vaccine candidate in turkeys. We found that MG ts-304 was able to colonise the trachea of 3-week-old turkeys and was safe, even at a tenfold overdose, inducing no adverse clinical signs of respiratory disease or significant gross lesions in the respiratory tract (air sacs or trachea), and was poorly transmissible to in-contact birds. We also showed that it was efficacious when administered to 3-week-old turkeys, inducing protective immunity against challenge with the M.gallisepticum wild-type strain Ap3AS. MG ts-304 is therefore a promising live attenuated vaccine candidate for use in turkeys.
鸡败血支原体（MG）是一种全球性的重要禽类病原体，可引起鸡慢性呼吸道病（CRD）和火鸡传染性窦炎。Vaxsafe MG（株 ts-11）是一种减毒活的温度敏感疫苗，已被证明能有效控制鸡的 CRD，但对火鸡无效。gapA 基因编码一种成熟的细胞黏附素蛋白，分子量约为 105 kDa，在株 ts-11 中不表达，因为 20 个碱基重复序列导致移码，并导致翻译肽的过早截短。从株 ts-11 中分离出的 GapA 阳性克隆 MG ts-304 已被证明在鸡中具有增强的功效。在这里，我们描述了我们进行的评估 MG ts-304 疫苗候选物在火鸡中的安全性和功效的研究。我们发现，MG ts-304 能够定植 3 周龄火鸡的气管，即使在十倍超剂量下也是安全的，不会引起呼吸道疾病的任何不良临床症状或呼吸道（气囊或气管）的明显大体病变，并且对接触到的鸟类的传染性很差。我们还表明，当给 3 周龄的火鸡接种时，它具有针对 M.gallisepticum 野生型菌株 Ap3AS 挑战的保护作用。因此，MG ts-304 是一种有前途的减毒活疫苗候选物，可用于火鸡。
