Expression of Factor X in BHK-21 Cells Promotes Low Pathogenic Influenza Viruses Replication.

Shahla Shahsavandi,Hasan Izadi,Mohammad Majid Ebrahimi,Shahin Masoudi

doi:10.1155/2015/675921

Shahla Shahsavandi, Hasan Izadi + Show 2 more

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https://doi.org/10.1155/2015/675921

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Abstract

A cDNA clone for factor 10 (FX) isolated from chicken embryo inserted into the mammalian cell expression vector pCDNA3.1 was transfected into the baby hamster kidney (BHK-21) cell line. The generated BHK-21 cells with inducible expression of FX were used to investigate the efficacy of the serine transmembrane protease to proteolytic activation of influenza virus hemagglutinin (HA) with monobasic cleavage site. Data showed that the BHK-21/FX stably expressed FX after ten serial passages. The cells could proteolytically cleave the HA of low pathogenic avian influenza virus at multiplicity of infection 0.01. Growth kinetics of the virus on BHK-21/FX, BHK-21, and MDCK cells were evaluated by titrations of virus particles in each culture supernatant. Efficient multicycle viral replication was markedly detected in the cell at subsequent passages. Virus titration demonstrated that BHK-21/FX cell supported high-titer growth of the virus in which the viral titer is comparable to the virus grown in BHK-21 or MDCK cells with TPCK-trypsin. The results indicate potential application for the BHK-21/FX in influenza virus replication procedure and related studies.

Highlights

Influenza is one of the most economically important viral respiratory diseases of human as well as avian and animal species worldwide
The ability of H9N2 influenza virus to infect the MDCK and BHK-21 cell lines was assessed in the absence and presence of supplemental trypsin
The H9N2 virus replicated in both cells and moderate cytopathic effect (CPE) were evident 48 hpi only in the presence of trypsin

Summary

Introduction

Influenza is one of the most economically important viral respiratory diseases of human as well as avian and animal species worldwide. Cellular tropism and the infectivity of influenza viruses are primarily determined by the distribution of these receptors in the cell surface. The presence of specific host cellular protease (s) for posttranslational cleavage of HA0 precursor protein is essential for viral infectivity, pathogenicity, and tissue tropism [7, 8]. Beside the viral tropism determined by virusreceptor interactions, local density of receptors, lipid raft microdomains, and host cell proteases activating the viral surface glycoproteins play major roles in influenza infectivity [14, 15]. The viruses have the ability to exploit a host virusactivating protease system to support own replication Cellular host proteases such as transmembrane serine proteases (TMPRSS), an analogous protease from chicken allantoic fluid to the blood clotting factor 10 (FX), and plasmin were involved in the postentry stages of influenza A virus infection

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