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Advances in Virology
Volume 2015 (2015), Article ID 675921, 6 pages
Research Article

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

Razi Vaccine & Serum Research Institute, P.O. Box 31975-148, Karaj 31976 19751, Iran

Received 3 October 2015; Revised 5 December 2015; Accepted 8 December 2015

Academic Editor: Subhash C. Verma

Copyright © 2015 Shahla Shahsavandi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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.