1997 Volume 8 Issue 1 Pages 7-11
Neutralization antigenic sites of equine arteritis virus (EAV) were examined with neutralization resistant (NR) mutants generated by two monoclonal antibodies (MAbs; 1A1 and 4G8). From the result of the neutralization test with NR mutants, each MAb was found to recognize a distinct neutralization antigenic site. Immunofluorescent test revealed that the MAbs bound to antigen expressed on the cell surface and envelope protein of the parental EAV-infected cells, but they lost binding activity to antigen in NR mutant-infected cells. The two neutralization MAbs were found to recognize ORF5-coding protein, GL protein, by sequence analysis of the structural protein-cording region of the parental virus and NR mutant genome. 1A1 and 4G8 recognized neutralization epitope including amino acid positions 60-61 and 84 of GL protein, respectively. The amino acid positions were located in or near the hydrophilic domain of GL protein, and hydrophilicity of the positions of NR mutants was distinct from the parental virus.