CLASSIFICATION OF A NEW MEMBER OF THE TBE FLAVIVIRUS SUBGROUP BY ITS IMMUNOLOGICAL, PATHOGENETIC AND MOLECULAR CHARACTERISTICS - IDENTIFICATION OF SUBGROUP-SPECIFIC PENTAPEPTIDES

The antigenic, pathogenic and molecular characteristics of Turkish she ep encephalitis (TSE) virus, strain TTE80, were compared with other me mbers of the tick-borne encephalitis (TBE) virus complex. Monoclonal a ntibodies with defined specificity for the flavivirus envelope glycopr otein distinguished TSE virus from louping ill (LI), western or far ea stern TBE, Langat and Powassan virus in indirect immunofluorescence, h aemagglutination-inhibition and neutralization tests. On the other han d, TSE virus, which produces an LI-like disease in sheep, resembled LI virus in mouse neurovirulence tests. Molecular homology data of all t he structural genes of TSE virus compared with other tick-borne flaviv iruses demonstrated that TSE virus is a distinct member in the TBE vir us subgroup. The data are consistent with the conclusion that TSE viru s has evolved by a separate evolutionary pathway as compared with the close antigenic relatives, western European, far eastern TBE viruses a nd LI virus. By aligning the encoded amino acids in the viral envelope glycoprotein of mosquito- and tick-borne flaviviruses, we have also i dentified subgroup-specific pentapeptide motifs for the tick-borne enc ephalitis, Japanese encephalitis and dengue subgroup viruses of the ge nus Flavivirus. These pentapeptides have important implications for th e evolution, classification and diagnosis of flaviviruses.