Recombinant IBV (B/Victoria/2/87) Hemagglutinin (a.a. 16-548) [His]

Influenza B virus (IBV) is one of the most important human respiratory viruses: it causes approximately one-third of the global influenza-related disease burden each year. However, compared with the several pathogenicity-related molecular markers that have been identified for influenza A virus (IAV), little is known about potential IBV pathogenicity-related markers. Here, although the IBV strain B/Anhui-Tunxi/1528/2014 (AH1528/14) exhibited a more efficient replication abilityin vitroand higher pathogenicityin vivocompared with IBV strain B/Anhui-Baohe/127/2015 (AH127/15), only three amino acids differences (HA(A390E), NA(N342D)and PB1(V212I)) were observed among their full genomes. The contributions of each amino acid difference to the virus pathogenicity were further investigated. Compared with the wild type IBV virus rAH127, the recombinant virus harbouring a single substitution of HA(A390E)had a similar phenotype, whereas the recombinant virus harbouring PB1(V212I)replicated to a moderately higher titre in both MDCK cells and in mice. Notably, the virus harbouring NA(N342D)showed significantly better growth properties in MDCK cells and higher fatality rates in mice. In addition, the presence of NA(N342D)dramatically enhanced the viral neuraminidase activity. In conclusion, our study identified a novel IBV molecular marker, NA(N342D), that could significantly increase the virulence of IBV in mice.

The present study was conducted to determine the antiviral activity of different Cholistani plants growing in the Cholistan Desert, Pakistan. Methanolic extracts of plants were prepared by dissolving air-dried, powdered plants in methanol and later concentrated in a rotary evaporator. The concentrated extracts were dissolved in distilled water and sterilized through filtration. To asses antiviral potential plant extracts were mixed with an equal concentration of a live virus and propagated for 7-11 days in embryonated eggs with appropriate controls. After 48 hours, the allantoic fluids were harvested and hemagglutination assay (HA) was performed for infectious bronchitis virus (IBV) and indirect hemagglutination assay (IHA) for infectious bursal disease virus (IBDV) to determine both virus titer, as well as evaluation of the inhibitory effects of various plant extracts. Almost all selected plant extracts exhibited an antiviral effect varying from plant to plant and manifested through controlling growth of IBV except Solanum surattense. The methanolic extracts of two plants Ochthochloa compressa and Sporobolos icolados, showed a 100% inhibitory effect demonstrated through no viral growth determined by HA assays. Similarly, other plant extracts also showed antiviral activity in the order of HA titer at 8 in case of three plants Haloxylon salicornicum, Neurada procumbens and Salsola baryosma, 16 for Achyranthes aspera, Haloxylon recurvum and Panicum antidotale. The HA values 32 and 64, respectively, for Oxystelma esculentum and Suaeda fruticosa were revealed. In case of anti-IBDV activity, the methanolic extracts of Achyranthes aspera, Haloxylon recurvum, Haloxylon salicornicum, Panicum antidotale, Salsola baryosma, Sporobolos icolados were shown to have the optimal antiviral potential (IHA titer 0). Similarly, extract of Neurada procumbens kept the IHA titer at 2 and Solanum surattense at 4. The extracts of Oxystelma esculentum and Ochthochloa compressa were least effective in controlling multiplication of IBDV and their IHA titer was equal to virus control. Overall, our studies open up new avenues in the development of much needed antivirals, utilizing indigenous resources. (C) 2016 PVJ. All rights reserved.