Narayan O, Clements J E, Griffin D E, Wolinsky J S
Infect Immun. 1981 Jun;32(3):1045-50. doi: 10.1128/iai.32.3.1045-1050.1981.
The visna viruses are antigenically related nononcogenic retroviruses of sheep. The original strain was isolated from the brain of a paralyzed sheep in Iceland during the 1940s. The prototype strains has been passed serially in sheep and has undergone progressive antigenic change. Previous reports have shown that such antigenic changes in visna virus can be reproduced in infected cell cultures treated with neutralizing antibody. We now show that the antigenic profiles of the emerging mutants directly reflect the nature of the selecting antibody. Mutants with minor antigenic changes were selected by "early" sera which had a limited neutralization range. Mutants with greater antigenic changes were selected by "late" sera with a wide neutralization range. Mutants selected by early sera emerged rapidly and consistently in cultures, and these were antigenically very similar to one another. Mutants rarely emerged in cultures treated with late sera, but these viruses showed major antigenic changes. The data suggest that the evolution of antigenic mutants of visna virus progresses by a series of minor mutations which accumulate under the selective pressure of antibody.
维斯纳病毒是绵羊的抗原相关非致瘤性逆转录病毒。最初的毒株于20世纪40年代从冰岛一只瘫痪绵羊的大脑中分离出来。原型毒株已在绵羊中连续传代，并发生了渐进性的抗原变化。先前的报告表明，在用中和抗体处理的感染细胞培养物中可以重现维斯纳病毒的这种抗原变化。我们现在表明，新出现的突变体的抗原谱直接反映了选择抗体的性质。具有轻微抗原变化的突变体由中和范围有限的“早期”血清选择。具有较大抗原变化的突变体由中和范围广泛的“晚期”血清选择。由早期血清选择的突变体在培养物中迅速且一致地出现，并且这些突变体在抗原性上彼此非常相似。在用晚期血清处理的培养物中很少出现突变体，但这些病毒显示出主要的抗原变化。数据表明，维斯纳病毒抗原突变体的进化是通过一系列在抗体选择压力下积累的微小突变进行的。
