[Highly-sensitive nonradioactive detection of the tick-borne encephalitis virus]. / Vysokochuvstvitel'naia neradioaktivnaia detektsiia virusa kleshchevogo éntsefalita.

The non-radioactive reverse dot-blot method was used for the detection of tick-borne encephalitis virus (TBEV) in clinical specimens. The method involves reverse transcription (RT) and polymerase chain reaction (PCR) using a pair of biotin-labelled oligonucleotide primers. These primers flank a region in the gene of the envelope protein E, which is more conserved than other regions, and initiate the polymerisation with RNAs of all the investigated strains. The amplified cDNA was captured from solution on a solid support using complementary oligonucleotides covalently bound to a polyamide membrane. The biotin labels of the resulting hybrids were visualized by means of the streptavidin-horseradish peroxidase conjugate. The detection limit of the test was about 10(3)-10(4) molecules of target RNA. The sensitivity was comparable to that obtained by dot-hybridization of PCR-product with 32P-labelled DNA probe. The method was used for the detection of RNA in specimens of tick and blood.

[Comparison of 3 express-methods of detection of tick-borne encephalitis virus]. / Sravnenie trekh ékspress-metodov indikatsii virusa kleshchevogo éntsefalita.

Comparative studies of the diagnostic value of three express methods for detection of tick-borne encephalitis virus in ticks (fluorescent antibody technique (FAT) enzyme immunoassay (EIA), and molecular hybridization of nucleic acids) and the traditional method (bioassay in white mice) showed all the three express methods to be rapid, specific, sensitive, and useful for large-scale epidemiological surveys. Notable was the high effectiveness of the method of nucleic acids hybridization which was not inferior to bioassays in suckling mice and exceeded FAT and EIA. The results of the latter seem to be affected by antigenic variations among tick-borne encephalitis virus strains.