Molecular and biological characteristics, and cultivation of an attenuated strain 1974-VNIIVViM of rift valley fever virus

Molecular and biological characteristics, and cultivation of an attenuated strain 1974-VNIIVViM of rift valley fever virus

2015

Imatdinov I.R. | Balysheva V.I. | Ponomarev V.N. | Kapustina O.V.

Russian. Возможность распространения лихорадки долины Рифт

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English. In recent decades, a threat of spreading Rift Valley fever (RVF) to Asia and Europe raises serious concerns. This work was aimed at molecular and biological characterization of an attenuated RVF virus (RVFV) strain 1974-VNIIVViM. The results of the investigations showed that the virus accumulated in continuous cell cultures like saiga kidney (SK), Siberian mountain goat kidney (PSGK-60) and MDVK (calve kidney cell culture) at high titers with infectious (8.53±0.21 lg MICLD50/cm3) and antigenic (1:64 to 1:128 in the passive hemagglutination test) activity levels. We determined optimal regime of the virus growth in BHK-21/13 (Syrian hamster kidney cell culture) using a roller culture method: the culture bottle rotation speed of 12 to 15 r.p.h., the infection dosage of 0.01 to 0.001 MLD50/cell, the first 12 hours of the culture at pH = 6.4 to 6.8. Further, pH is maintained at 7.2 to 7.6 for 48 to 72 hours of culture at 37 deg С, which provides the raw virus production at high infectivity and antigenicity levels. Phylogenetic analysis of the nucleotide sequences of 3 sites in S and/or M segments showed that it was closely related to strains Smithburn and Entebbe. Comparative analysis of nucleotide sequences of genes encoding glycoproteins Gn and Gc, and the nucleoprotein N, shows that most of the substitutions in the sequences of the genes of the RVFV strain 1974-VNIIVViM are synonymous and do not alter the primary amino acid sequence, with insertion and deletion missing. In the nucleotide sequence encoding glycoprotein Gn we found 8 substitutions relative to a similar sequence of M segment of a virulent strain Entebbe, and 14 substitutions when compared with M segment of strain Smithburn. A lower (as compared with other attenuated strains) amount of significant amino acid substitutions in RVFV antigenic components was revealed.

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Bibliographic information

Agricultural Biology

Volume

50

ISSN

0131-6397

Translated Title

Оптимизация культивирования и молекулярно-биологическая характеристика аттенуированного штамма 1974-ВНИИВВиМ вируса лихорадки долины рифт