Bolwell C, Brown A L, Barnett P V, Campbell R O, Clarke B E, Parry N R, Ouldridge E J, Brown F, Rowlands D J
Wellcome Biotechnology Limited, Beckenham, Kent, U.K.
J Gen Virol. 1989 Jan;70 ( Pt 1):45-57. doi: 10.1099/0022-1317-70-1-45.
Foot-and-mouth disease virus (FMDV) A22 Iraq 24/64 adapted to grow in BHK monolayer cells induced antibodies which neutralized many isolates belonging to the A serotype. Plaque-purified virus isolated from this stock also induced broadly reactive antibodies, showing that this property is not due to the combined response to a mixture of variants in the original stock virus. However, viruses obtained by passage in suspension BHK cells of either the monolayer cell-adapted virus or a virus cloned from this stock resulted in the selection of virus which induced antibodies with highly specific neutralizing activity. In addition to their antigenic properties the monolayer and suspension cell-adapted viruses could be distinguished by plaque morphology, tendency to aggregate and ability to attach to BHK cells. Monoclonal antibodies (MAbs) induced with the plaque-purified monolayer-adapted virus had neutralizing activity almost as broad as polyclonal serum, showing that this property can be represented by a single epitope on the virus. These neutralizing MAbs recognize a trypsin-sensitive epitope on the virus. Surprisingly, sequence analysis of the structural protein-coding regions of the genomic RNAs of monolayer and suspension cell-adapted viruses showed no amino acid differences in VP1, the protein known to contain the major neutralization epitope in FMDV and to be the only protein susceptible to cleavage by trypsin in the virus particle. Although three coding differences were found in the capsid protein these were all located in VP2.
适应在BHK单层细胞中生长的口蹄疫病毒（FMDV）A22伊拉克24/64毒株诱导产生的抗体能中和许多属于A血清型的分离株。从该毒株中分离得到的经空斑纯化的病毒也诱导产生了广泛反应性抗体，表明这种特性并非源于对原始毒株中多种变异体混合物的联合反应。然而，通过在悬浮培养的BHK细胞中传代单层细胞适应病毒或从该毒株克隆的病毒所获得的病毒，导致选择出了诱导具有高度特异性中和活性抗体的病毒。除了它们的抗原特性外，单层细胞适应病毒和悬浮细胞适应病毒还可以通过空斑形态、聚集倾向以及与BHK细胞的附着能力来区分。用经空斑纯化的单层细胞适应病毒诱导产生的单克隆抗体（MAb）具有几乎与多克隆血清一样广泛的中和活性，表明这种特性可以由病毒上的单个表位来体现。这些中和性单克隆抗体识别病毒上一个对胰蛋白酶敏感的表位。令人惊讶的是，对单层细胞适应病毒和悬浮细胞适应病毒的基因组RNA的结构蛋白编码区进行序列分析发现，VP1（已知在FMDV中包含主要中和表位且是病毒颗粒中唯一易被胰蛋白酶切割的蛋白）没有氨基酸差异。尽管在衣壳蛋白中发现了三个编码差异，但这些差异都位于VP2中。
