title: Mutation analysis of the cross-reactive epitopes of Japanese encephalitis virus envelope glycoprotein.
abstract: 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.
authors.affiliation: Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan, ROC.
authors.forename: Shyan-Song
authors.initials: SS
authors.lastname: Chiou
authors.affiliation: Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan, ROC.
authors.forename: Yi-Chin
authors.initials: YC
authors.lastname: Fan
authors.affiliation: Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, CO, USA.
authors.forename: Wayne D
authors.initials: WD
authors.lastname: Crill
authors.affiliation: Institute of Biotechnology and Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC.
authors.forename: Ruey-Yi
authors.initials: RY
authors.lastname: Chang
authors.affiliation: Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, CO, USA.
authors.forename: Gwong-Jen J
authors.initials: GJ
authors.lastname: Chang
mesh_terms: D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000276:immunology; D003429:Cross Reactions; D004252:DNA Mutational Analysis; D004664:Encephalitis Virus, Japanese / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D004672:Encephalitis, Japanese / Q000276:immunology / Q000821:virology*; D018604:Epitope Mapping; D000939:Epitopes / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D006801:Humans; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D008969:Molecular Sequence Data; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D000939:Epitopes; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins; C080628:glycoprotein E, Japanese encephalitis virus