Turner C M
Division of Infection and Immunity, I.B.L.S., University of Glasgow, UK.
FEMS Microbiol Lett. 1997 Aug 1;153(1):227-31. doi: 10.1111/j.1574-6968.1997.tb10486.x.
Rates of antigenic variation were measured in vivo in several populations of cloned lines of Trypanosoma brucei before and after cyclical transmission through tsetse flies. Two cloned lines were adapted for use in laboratory conditions by extensive syringe passaging and rates of antigenic switching/cell/generation were less than 3 x 10(-6) and 1 x 10(-4) in each line. Rates of switching were then determined after fly transmission of the first line and generated per capita rate values of greater than 2 x 10(-3) in three of four populations examined. In the fourth population the switch rate was lower: less than 7 x 10(-5) switches/ cell/generation. These data show that rates of antigenic variation are several orders of magnitude lower in syringe-passaged lines, such as those routinely used in the majority of laboratory studies, compared with most recently fly-transmitted lines. They also show that the reduction in switching rate associated with syringe passaging is reversible and is thus unlikely to be caused by mutation.
在通过采采蝇进行周期性传播之前和之后，在布氏锥虫克隆系的几个群体中对体内抗原变异率进行了测量。通过广泛的注射器传代使两个克隆系适应实验室条件，每个系中抗原转换/细胞/代的速率分别小于3×10⁻⁶和1×10⁻⁴。然后在第一个系经采采蝇传播后确定转换速率，在所检查的四个群体中的三个群体中产生的人均速率值大于2×10⁻³。在第四个群体中，转换速率较低：小于7×10⁻⁵转换/细胞/代。这些数据表明，与最近经采采蝇传播的系相比，在注射器传代系（例如大多数实验室研究中常规使用的系）中，抗原变异率要低几个数量级。它们还表明，与注射器传代相关的转换速率降低是可逆的，因此不太可能是由突变引起的。
