Evolution of New Variants/Mutants of JE Virus, Its Effect on Neurovirulence, Antigenicity, Host Immune Responses and Disease Transmission in Endemic Areas

Table 1

Evolutionary mechanisms involved in formation of new JE virus variants/mutants.

Mechanism	Mutation type	Possible genomic change	Antigenicity	Neurovirulence	Endemicity	Therapeutics	References
Natural	Substitutions	Epitope/specific	Positive/high	High	Increase	Live attenuated vaccines	[1, 22, 79, 80]
	Deletions	Epitope/specific	Positive/high	High	Decrease	Live attenuated vaccines	[39, 172]
	Reversions	Epitope/specific	Negative/low	Low	Mild	Chimeric vaccines	[1, 171]
	Duplications	Nonspecific	Negative/low	Low	Increase	RNA/Degenerated vaccines
	Rearrangements	Nonspecific	Negative/low	Low	Constant	RNA/Degenerated vaccines	[97, 109]
	Reassortment	Nonspecific	Negative/low	Low	Constant	RNA/Degenerated vaccines	[110]
Artificial	Site directed mutagenesis	Epitope/desirable	Positive/negative	High	Increase	Live attenuated vaccines	[1]
	Fusion of proteins	Epitope/desirable	Positive/negative	High	Increase	Live attenuated vaccines	[61, 62, 175]
	Chimerization	Epitope/desirable	Positive/high	High	Increase	Chimeric vaccines	[174, 179]
	cDNA clones	Epitope/desirable	Positive/negative	High	Increase	Recombinant vaccines	[83, 87]
	VLPs	Epitope/desirable	Positive/high	High	Increase	Recombinant vaccines	[61, 62]
	Recombinant viruses	Epitope/desirable	Positive/high	High	Increase	Recombinant vaccines	[101]
	Vaccines strains	Epitope/desirable	Positive/low	Mild	Increase	Live attenuated vaccines	[167]
	Synthetic antigens	Short peptides	Positive/negative	High	Increase	Attenuated vaccines
Recombination	Homologous	Epitopic/nonspecific	Positive/high	High	Increase	Recombinant vaccines	[101, 104, 108]
	Intertypic	Epitopic/nonspecific	Positive/mild	High	Increase	Recombinant vaccines	[111]
	Intratypic	Epitopic/nonspecific	Positive/mild	High	Increase	Recombinant vaccines	[105]
Replication	Shared	Epitopic/nonepitopic	Positive/high	High	Increase	Attenuated vaccines	[39, 41]