Mutation analysis of the cross-reactive epitopes of Japanese encephalitis virus envelope glycoprotein

• Published in: Journal of general virology Vol. 93; no. 6; pp. 1185 - 1192
• Main Authors: Chiou, Shyan-Song, Fan, Yi-Chin, Crill, Wayne D., Chang, Ruey-Yi, Chang, Gwong-Jen J.
• Format: Journal Article
• Language: English
• Published: Reading Society for General Microbiology 01.06.2012
• Subjects: Amino Acid Sequence; amino acid substitution; amino acids; Antibodies, Viral - immunology; Biological and medical sciences; cross reaction; Cross Reactions; DNA Mutational Analysis; Encephalitis Virus, Japanese - chemistry; Encephalitis Virus, Japanese - genetics; Encephalitis Virus, Japanese - immunology; Encephalitis, Japanese - immunology; Encephalitis, Japanese - virology; Epitope Mapping; epitopes; Epitopes - chemistry; Epitopes - genetics; Epitopes - immunology; Flavivirus; Fundamental and applied biological sciences. Psychology; genes; glycoproteins; Humans; Japanese encephalitis virus; Membrane Glycoproteins - chemistry; Membrane Glycoproteins - genetics; Membrane Glycoproteins - immunology; Microbiology; Miscellaneous; Molecular Sequence Data; monoclonal antibodies; mutants; plasmids; site-directed mutagenesis; Viral Envelope Proteins - chemistry; Viral Envelope Proteins - genetics; Viral Envelope Proteins - immunology; Virology; virus-like particles; Virus; Antigenic determinant; Glycoprotein; Japanese encephalitis virus; Japanese encephalitis group virus; Mutation; Flaviviridae; Flavivirus
• DOI: 10.1099/vir.0.040238-0
• ISSN: 0022-1317; 1465-2099

Group and serocomplex cross-reactive epitopes have been identified in the envelope (E) protein of several flaviviruses and have proven critical in vaccine and diagnostic antigen development. Here, we performed site-directed mutagenesis across the E gene of a recombinant expression plasmid that encodes the Japanese encephalitis virus (JEV) premembrane (prM) and E proteins and produces JEV virus-like particles (VLPs). Mutations were introduced at I135 and E138 in domain I; W101, G104, G106 and L107 in domain II; and T305, E306, K312, A315, S329, S331, G332 and D389 in domain III. None of the mutant JEV VLPs demonstrated reduced activity to the five JEV type-specific mAbs tested. Substitutions at W101, especially W101G, reduced reactivity dramatically with all of the flavivirus group cross-reactive mAbs. The group and JEV serocomplex cross-reactive mAbs examined recognized five and six different overlapping epitopes, respectively. Among five group cross-reactive epitopes, amino acids located in domains I, II and III were involved in one, five and three epitopes, respectively. Recognition by six JEV serocomplex cross-reactive mAbs was reduced by amino acid substitutions in domains II and III. These results suggest that amino acid residues located in the fusion loop of E domain II are the most critical for recognition by group cross-reactive mAbs, followed by residues of domains III and I. The amino acid residues of both domains II and III of the E protein were shown to be important in the binding of JEV serocomplex cross-reactive mAbs.