Markham J F, Morrow C J, Whithear K G
School of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia.
Avian Dis. 1998 Oct-Dec;42(4):671-6.
A temperature-sensitive clone of Mycoplasma synoviae (MS), MS-H, derived from the chemical mutagenesis of the Australian field isolate 86079/7NS, was investigated for efficacy as a live vaccine. Titers of MS-H vaccine ranged between 1.16 x 10(8) and 8.4 x 10(8) color changing units/ml when incubated at 33 C and were consistently > or = 10(2) lower when incubated at 39.5 C. Laboratory-produced MS-H vaccine protected 8 out of 10 specific-pathogen-free Webster white leghorn chickens against a combined experimental challenge of aerosols of the virulent wild MS strain 88064/FP and T-strain infectious bronchitis vaccine administered intratracheally. Laboratory and commercially produced vaccines were compared for efficacy against thoracic air sac challenge, with both achieving similar levels of air sac protection. Air sac lesion incidences of five air sacs with lesions out of 32 and four out of 32 were seen in groups vaccinated with laboratory and commercial vaccines, respectively, compared with 13 out of 20 in nonvaccinated specific-pathogen-free hybrid white leghorn chickens. An attempt to determine the dose response of the commercial vaccine was conducted with 0.5, 2, and 4 times the standard dose. Air sac lesion incidences of 16 air sacs with lesions out of 32 in the 0.5 times, 11 out of 32 in the 2 times, and 1 out of 32 in the 4 times dose groups were observed.
对源自澳大利亚田间分离株86079/7NS化学诱变的滑膜支原体（MS）温度敏感克隆MS-H作为活疫苗的效力进行了研究。MS-H疫苗在33℃孵育时滴度范围为1.16×10⁸至8.4×10⁸个颜色变化单位/毫升，而在39.5℃孵育时始终低10²倍以上。实验室生产的MS-H疫苗保护了10只无特定病原体的韦伯斯特白来航鸡中的8只，使其免受强毒野生MS菌株88064/FP气溶胶和经气管内接种的T株传染性支气管炎疫苗联合实验攻击。比较了实验室生产的疫苗和商业生产的疫苗对胸气囊攻击的效力，两者的气囊保护水平相似。接种实验室疫苗和商业疫苗的组中，分别有32个气囊中有5个和4个出现气囊病变，相比之下，未接种疫苗的无特定病原体杂交白来航鸡中20个中有13个出现气囊病变。尝试用标准剂量的0.5、2和4倍来确定商业疫苗的剂量反应。在0.5倍剂量组中，32个气囊中有16个出现气囊病变；在2倍剂量组中，32个中有11个出现病变；在4倍剂量组中，32个中有1个出现病变。
