AGRICULTURAL BIOLOGY, 2015, V. 50, ¹ 6, pp. 794-802 ISSN 2412-0324 (English ed. Online) (SEL’SKOKHOZYAISTVENNAYA BIOLOGIYA) ISSN 0131-6397 (Russian ed. Print) ISSN 2313-4836 (Russian ed. Online) doi: 10.15389/agrobiology.2015.3.794rus doi: 10.15389/agrobiology.2015.3.794eng MOLECULAR AND BIOLOGICAL CHARACTERISTICS, AND CULTIVATION OF AN ATTENUATED STRAIN 1974-VNIIVViM OF RIFT VALLEY FEVER VIRUS I.R. IMATDINOV, V.I. BALYSHEVA, V.N. PONOMAREV, O.V. KAPUSTINA Federal Agency of Scientific Organizations, Pokrov, Petushinskii Region, Vladimir Province, 601120 Russia, e-mail VNIIVViM@niiv.petush.elcom.ru, ilnazicf@ya.ru, balyvi@uandex.ru A b s t r a c t In recent decades, a threat of spreading Rift Valley fever (RVF) to Asia and Europe raises serious concerns. <...> Within many years, vaccines against RVF were developed in several ways including designing attenuated vaccine versions, inactivated or genetically engineered vaccines. <...> A serious hazard of the RVF agent requires developing sufficiently immunogenic preparations providing both RVF specific prevention and safety precautions in production procedures. <...> Therefore, this work was aimed at molecular and biological characterization of an attenuated RVF virus (RVFV) strain 1974VNIIVViM including search for high-tech cell culture systems for the virus growth and determination of its antigenic and/or immunogenic relationship with a virulent strain Entebbe. <...> 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, PHT) 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. <...> 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 allowing their grouping into a separate cluster. <...> Comparative analysis of nucleotide sequences of genes encoding glycoproteins Gn <...>