Carrillo C, Plana J, Mascarella R, Bergadá J, Sobrino F
Departamento de Sanidad Animal, INIA, Madrid, Spain.
Virology. 1990 Dec;179(2):890-2. doi: 10.1016/0042-6822(90)90162-k.
A plaque-purified preparation of foot-and-mouth disease virus (FMDV) of serotype C1 (C-S8c1-1), grown in cell culture, was used to infect nonimmunized pigs. No variant genomes were detected in the average populations of 50 viruses isolated from infected animals by direct RNA sequencing of the carboxy-terminal half of the VP1 gene. However, a mutant with altered phenotypic properties was present in low proportion in an infected animal. The frequency of mutants resistant to neutralization by SD6 monoclonal antibody (MAb) [SD6 epitope MAb-resistant mutants (MARMs)], directly estimated in virus from lesions of infected animals (without passage in cell culture), depended on the procedure used for its determination and ranged from 2.9 x 10(-6) (when the virus was incubated with the MAb prior to plating) to 2.6 x 10(-5) (when incubation with MAb was avoided and the MAb was maintained in the agar overlay of the titration assay). Such a difference was not found for C-S8c1-1, which consistently showed frequencies of about 4 x 10(-5). In addition, the repertoire of amino acid substitutions was similar among SD6 epitope MARMs isolated directly both from vesicles of infected animals and from C-S8c1-1. Thus, in spite of the conservation of the average sequence in the region of VP1 RNA analyzed, antigenic heterogeneity has been found in viral populations of FMDV upon replication in nonimmunized swine.
在细胞培养中生长的C1血清型口蹄疫病毒（FMDV）（C-S8c1-1）的噬斑纯化制剂用于感染未免疫的猪。通过对VP1基因羧基末端一半进行直接RNA测序，从感染动物分离的50种病毒的平均群体中未检测到变异基因组。然而，在一只感染动物中存在低比例的具有改变表型特性的突变体。直接在感染动物病变部位的病毒中（未在细胞培养中传代）估计对SD6单克隆抗体（MAb）产生中和抗性的突变体频率[SD6表位单克隆抗体抗性突变体（MARM）]，取决于用于测定的程序，范围从2.9×10^(-6)（当病毒在铺板前与MAb孵育时）到2.6×10^(-5)（当避免与MAb孵育且MAb保持在滴定试验的琼脂覆盖层中时）。对于C-S8c1-1未发现这种差异，其始终显示频率约为4×10^(-5)。此外，直接从感染动物水疱和C-S8c1-1分离的SD6表位MARM之间的氨基酸取代谱相似。因此，尽管在分析的VP1 RNA区域平均序列保守，但在未免疫猪中复制时，FMDV病毒群体中已发现抗原异质性。
