Bock R E, de Vos A J, Lew A, Kingston T G, Fraser I R
Tick Fever Research Centre, Wacol, Queensland.
Aust Vet J. 1995 Aug;72(8):296-300. doi: 10.1111/j.1751-0813.1995.tb03558.x.
Field investigations of the protection afforded by the Australian live Babesia bovis vaccine used in the early 1990s (T strain) revealed inadequate vaccine-induced protection in certain herds. Vaccination/challenge trials using 207 experimental cattle were conducted to evaluate the protection afforded by T strain B bovis against field isolates from these herds. The trials investigated whether isolates that could 'break-through' T strain immunity were present in the field, the ability or inability of specific cattle to develop protective immunity after vaccination with T strain and the effect of attenuation and maintenance procedures on the immunogenicity of T strain. The results showed that B bovis parasites present early in the process of attenuation of T strain were more protective than those remaining late in the process. They also showed that cattle from properties experiencing vaccine failures were less protected by T strain vaccination than Bos taurus cattle randomly selected from the general population if vaccinated with highly attenuated T strain. A hypothesis is offered to explain these findings.
对20世纪90年代初使用的澳大利亚活牛巴贝斯虫疫苗（T株）所提供保护的现场调查显示，在某些牛群中，疫苗诱导的保护作用不足。使用207头实验牛进行了接种/攻毒试验，以评估T株牛巴贝斯虫对这些牛群野外分离株的保护作用。试验调查了野外是否存在能够“突破”T株免疫的分离株、特定牛在接种T株后产生保护性免疫的能力或无此能力，以及减毒和保存程序对T株免疫原性的影响。结果表明，T株减毒过程早期存在的牛巴贝斯虫寄生虫比后期残留的更具保护作用。他们还表明，如果用高度减毒的T株进行接种，来自疫苗接种失败牧场的牛比从普通牛群中随机选择的金牛座牛受到T株疫苗接种的保护更少。本文提出了一个假设来解释这些发现。
