Vol 56, No 3 (2011)

The authors have obtained a panel of 7 monoclonal antibodies (MAbs) against pandemic influenza virus A/IIV-Moscow/01/2009 (H1N1)swl isolated in Russia. One MAb is directed to a NP protein linear epitope and interacts with all the influenza A viruses under study. Six other MAbs are directed to H1 hemagglutinin conformation-dependent determinants and detect homologous virus in the hemagglutination-inhibition test, enzyme immunoassay, immunofluorescence and virus neutralization tests. MAbs differentiate pandemic influenza viruses A(H1N1)swl from seasonal influenza A(H1N1), A(H3N2), and B viruses. The high neutralizing activity of MAbs permits their use to study the fine antigen structure of influenza virus hemagglutinin and to differentiate the A(H1N1) pandemic influenza viruses and offers promise for obtaining humanized antibodies in order to make specific prevention and treatment of influenza.

Infectivity of pandemic influenza virus A(H1N1) infectivity is shown to be activated through proteolytic cleavage of hemagglutinin HA0 → HA1 + HA2 during virus propagation in the human intestinal cell line Caco-2 and chicken embryonated eggs. Injection of aprotinin, a natural serine protease inhibitor, into the liquid culture or allantoic cavity of chicken embryos inhibited the proteolysis of the viral HA0 and suppressed the proteolytic activation of the synthesized virus and its multicycle replication. These data allow aprotinin to be recommended as an antiviral drug for the treatment of swine influenza in humans.

The authors studied the prevalence of mutations associated with resistance to the CCR5 coreceptor antagonists maraviroc and vicriviroc in Russia. Most (93.6%) patients infected with HIV-1 genetic subtype A (IDU-A), predominant in the CIS countries, were found to have maraviroc resistance mutations. These mutations appear to reflect the natural genome polymorphism characteristic of the variant IDU-A. Maraviroc resistance mutations were of limited occurrence (2.8%) among the samples of virus subtype B in Russia. There were no vicriviroc resistance mutations in both the HIV-1 genetic variant IDU-A and the samples of virus subtype B. There is a need for further clinical studies evaluating the real impact of these mutations on the efficacy of maraviroc in patients infected with the HIV-1 genetic variant IDU-A.

Long-term monitoring of natural tick-borne encephalitis virus (TBEV) populations could reveal the change of TBEV subtypes, the displacement of the Far Eastern (FE) subtype, and its substitution for the Siberian (Sib) subtype. Acute and inapparent mixed infections were studied in Syrian hamsters to understand this phenomenon. The animals were inoculated with the Sib subtype and then with the FE one of TBEV (JQ845440-Yaroslavl-Aver-08 and Fj214132-Kemerovo-Phateev-1954 strains). The inapparent form developed more frequently in mixed infection. Viral progeny was genotyped by reverse transcription polymerase chain reaction and hybridization fluorescence detection using genotype-specific probes. Independent reproduction of strains in the brain gave way to competition. The FE subtype dominated in hamster youngsters with acute infection. The Sib subtype had selective benefits in asymptomatic infection (adult hamsters infected intracerebrally and subcutaneously and youngsters infected subcutaneously). The competition of the subtypes was imperfect.