[Deoxyoligonucleotide probes that differentiate antigenic and pathogenetic variants of the tick-borne encephalitis...

Experiments on molecular hybridization were carried out using a panel of 11 deoxyoligonucleotide probes complementary to different parts of tick-borne encephalitis (TBE) virus, strain Sophyin, genome. Under study were the TBE virus strains differing by 3 criteria: (1) source of isolation (patients with acute and chronic TBE, Ixodes persulcatus and D. nuttalli ticks, small mammals); (2) serotype (eastern and Siberian Aina/1448), (3) virulence for Syrian hamsters. RNA of all the strains was hybridized with kDNA, 90% of strains with probe Sh5 complementary to protein E gene, nucleotide positions 1285-1311. The highest differentiating capacity was observed with probes P131 and Sh3 complementary to genes of proteins ns2b and M. These probes reacted with RNA of 100% of highly virulent strains of the eastern serotype and only with 20-30% of strains of the Aina/1448 serotype of lower virulence. A certain differentiating capacity was demonstrated by probes Sh2 and P10 complementary to genes of prm and C proteins: they hybridized with RNA of 80% of eastern serotype strains highly virulent for hamsters and with only 20% of Aina/1448 serotype strains of low virulence. The panel of probes used revealed no significant differences among strains in relation to their isolation source, with the exception of a strain isolated from D. nuttalli ticks which reacted only with kDNA and probe P2 complementary to nsI protein gene, but not with other probes. The TBE virus strains isolated from patients with chronic TBE were shown to represent a genetically heterogeneous group.