[Monoclonal antibodies to highly pathogenic avian influenza A(H5N1) strain isolated in the Russian Federation: development and properties].

Highly pathogenic avian influenza (HPAI) virus subtype H5N1 has recently caused extensive epizootics in different regions of the world and presents a serious threat to man. Since 2005, HPAI virus subtype H5N1 strains have been circulating in Russia, which differ from the earlier isolated Southern Asia strains. A panel from 15 monoclonal antibodies (Mabs) to HPAI virus A/duck/Novosibirsk/56/05 (H5N1) was developed. Eleven Mabs interacted with the hemagglutinin molecule (HA), 4 with influenza A virus nucleoprotein (NP) in the Western blot assay. The bulk of the obtained Mabs interacted with homologous virus in ELISA and showed an antigen in the infected cells in the indirect immunofluorescence assay. Nine Mabs were active in the hemagglutination inhibition (HI) assay and 8 of them were capable to neutralize viral activity. The comparative analysis of the properties of Mabs in the HI assay using various influenza A strains showed that Mabs 2C6, 6F3, 4G10, 3G9, and 7B3 inhibited hemagglutination of study avian influenza viruses subtype H5, Mab 6F3 being most active. Mab 3B5 reacted only with the viruses isolated in the Russian Federation in 2005-2007 and failed to interact with the other study influenza A viruses subtype H5. The obtained panel of Mabs can be used to study the fine antigenic structure of hemagglutinin and to make a differential diagnosis of avian influenza viruses subtype A/H5N1. The high neutralizing activity of Mabs creates a prospect for preparing humanized antibodies for specific prevention and treatment.