Identification of neutralization-associated sites of enterovirus 70.

Abstract

Enterovirus 70 (EV70), the causative agent of acute haemorrhagic conjunctivitis (AHC) is a picornavirus with a number of unique biological and pathogenic properties. In vivo, EV70 shows tropism for the conjunctiva and in rare cases, can infect the central nervous system, while in vitro, it has the ability to infect a wide range of mammalian cells in culture. The main objective of this study was to identify sites associated with neutralization of EV70. Identification of neutralization-associated sites is an initial stage for producing subunit vaccines, and neutralizing monoclonal antibodies produced against these sites may have direct application as therapeutic agents. Several different monoclonal antibodies which have neutralizing activity against the prototype EV70 J670 were tested. Two antibodies yielded resistant virus plaques. The nucleotide sequence of the capsid protein-coding region of each mutant was determined following cDNA synthesis, PCR amplification and cloning. The deduced amino acid sequences of the capsid protein-coding regions were compared with the corresponding sequences from the EV70 prototype and several wild isolates of EV70. Amino acid residues that correlated with escape from neutralization were identified. Two neutralization associated determinants were identified on VP1 and VP2. The locations of these sites were compared with neutralization associated sites of other picornaviruses.