"Western blot showing differing mobility of E proteins from nine plaque-purified variants of West Nile virus (WNV) strain TM-171 Mex03. Nucleotide sequencing of strains in lanes 5 to 9 indicated the presence of an ""NYS"" glycosylation motif at residues 154 to 156 of E, while strains in lanes 1 to 4 encoded ""NYP."" Antigens were separated in a nonreducing 5%/10% discontinuous sodium dodecyl sulfate–polyacrylamide gel, transferred to 0.2 μm nitrocellulose and detected with WNV-specific monoclonal ant"