Dyson D A, Smith G R
Res Vet Sci. 1976 Mar;20(2):185-90.
The virulence of Mycoplasma mycoides for mice, which appears to parallel virulence for cattle, was assessed in respect of four vaccine strains well known for their use in the control of contagious bovine pleuropneumonia. The T1 strain was slightly more virulent than V5, and both were much more virulent than F and KH3J, which could not be distinguished from each other. There was no significant difference between cultures of the T1 strain supplied by three different vaccine-producing laboratories, The mousevirulence test was also used to study the effect of serial passage in artificial systems on virulent field strains of M mycoides; two such strains underwent no appreciable change in virulence during many passages in chick embryos or in mice, although the same strains, and two others, were readily attenuated by repeated subculture in broth. With one strain of M mycoides there was evidence that the total number of subcultures in broth over a given period was more important than the duration of each subculture.
针对四种因用于控制牛传染性胸膜肺炎而闻名的疫苗株，评估了丝状支原体对小鼠的毒力，其对小鼠的毒力似乎与对牛的毒力相当。T1株的毒力略高于V5株，且二者的毒力均远高于F株和KH3J株，F株和KH3J株之间无法区分。由三个不同疫苗生产实验室提供的T1株培养物之间没有显著差异。小鼠毒力试验还用于研究在人工系统中连续传代对丝状支原体强毒田间菌株的影响；两株这样的菌株在鸡胚或小鼠中多次传代期间毒力没有明显变化，尽管相同的这两株菌株以及另外两株菌株通过在肉汤中反复传代很容易被减毒。对于一株丝状支原体，有证据表明在给定时期内在肉汤中的传代总数比每次传代的持续时间更重要。
