Sáiz J C, Cairó J, Medina M, Zuidema D, Abrams C, Belsham G J, Domingo E, Vlak J M
Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Spain.
J Virol. 1994 Jul;68(7):4557-64. doi: 10.1128/JVI.68.7.4557-4564.1994.
A foot-and-mouth disease virus (FMDV) cDNA cassette containing sequences encoding the capsid precursor P1, peptide 2A and a truncated 2B (abbreviated P1-2A) of type C FMDV, has been modified to generate the authentic amino terminus and the myristoylation signal. This construct has been used to produce a recombinant baculovirus (AcMM53) which, upon infection of Spodoptera frugiperda insect cells, expressed a recombinant P1-2A precursor with a high yield. This polyprotein reacted with neutralizing monoclonal antibodies (MAbs) that bind to continuous epitopes of the major antigenic site A (also termed site 1) of capsid protein VP1. Unexpectedly, it also reacted with neutralizing MAbs which define complex, discontinuous epitopes previously identified on FMDV particles. The reactivity of MAbs with P1-2A was quantitatively similar to their reactivity with intact virus and, in both cases, the reactivity with MAbs that recognized discontinuous epitopes was lost upon heat denaturation of the antigen. The finding that a capsid precursor may fold in such a way as to maintain discontinuous epitopes involved in virus neutralization present on the virion surface opens the possibility of using unprocessed capsid precursors as novel antiviral immunogens.
一个包含编码口蹄疫病毒C型衣壳前体P1、肽2A和截短的2B（简称为P1-2A）序列的口蹄疫病毒（FMDV）cDNA盒已被修饰，以产生真实的氨基末端和豆蔻酰化信号。该构建体已用于生产重组杆状病毒（AcMM53），该病毒感染草地贪夜蛾昆虫细胞后，能高产表达重组P1-2A前体。这种多蛋白与结合衣壳蛋白VP1主要抗原位点A（也称为位点1）连续表位的中和单克隆抗体（MAbs）发生反应。出乎意料的是，它还与定义先前在FMDV颗粒上鉴定出的复杂、不连续表位的中和MAbs发生反应。MAbs与P1-2A的反应性在定量上与其与完整病毒的反应性相似，并且在这两种情况下，抗原热变性后与识别不连续表位的MAbs的反应性均丧失。衣壳前体可能以一种能够维持病毒体表面存在的参与病毒中和的不连续表位的方式折叠，这一发现为将未加工的衣壳前体用作新型抗病毒免疫原开辟了可能性。
