title: Pathologic potential of variant clones of the oshima strain of far-eastern subtype tick-borne encephalitis virus.
abstract: Tick-borne encephalitis virus (TBEV) is a zoonotic agent that causes acute central nervous system (CNS) disease in humans. We previously suggested that immune response in addition to CNS infection contribute to mouse mortality following TBEV infection. However, we did not examine the influence of virus variants in the previous study. Therefore, in this study, we investigated the biological and pathologic potentials of the variant clones in the TBEV Oshima strain. We isolated eight variant clones from the stock virus of the Oshima 5-10. These variants exhibited different plaque morphologies in BHK cells and pathogenic potentials in mice. Full sequences of viral genomes revealed that each of the variant clones except one had specific combinations of nucleotide and amino acid changes at certain positions different from the parent strain. We also showed that an amino acid substitution of Glu122→Gly in the E protein could have affected virus infection and replication in vivo, as well as the attenuated pathogenicity in mice. These data confirm the presence of virus variants or quasispecies from the parent strain. Further elucidation of the effect of each variant clone on immune responses such as the T-cell response is an important priority in the development of an effective vaccine and treatment strategies for tick-borne encephalitis.
authors.affiliation: Department of Virology, Institute of Tropical Medicine, Nagasaki University.
authors.forename: Le Xuan
authors.initials: le X
authors.lastname: Luat
authors.affiliation: Department of Virology, Institute of Tropical Medicine, Nagasaki University.
authors.forename: Mya Myat Ngwe
authors.initials: MM
authors.lastname: Tun
authors.affiliation: Department of Virology, Institute of Tropical Medicine, Nagasaki University.
authors.forename: Corazon C
authors.initials: CC
authors.lastname: Buerano
authors.affiliation: Department of Virology, Institute of Tropical Medicine, Nagasaki University.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Aoki
authors.affiliation: Department of Virology, Institute of Tropical Medicine, Nagasaki University.
authors.forename: Kouichi
authors.initials: K
authors.lastname: Morita
authors.affiliation: Department of Virology, Institute of Tropical Medicine, Nagasaki University.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hayasaka
keywords: E protein; Far-eastern subtype TBEV; variant clones