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Introduction: Inactivated influenza vaccines are traditionally produced in chicken embryonated eggs but its limitations in producing the required doses in pandemic outbreaks quickly enough has made searching for alternative modes of production necessary. The use of cell culture-based vaccine production is one way of overcoming the limitations of the egg-based method and securing a more rapid response.  Although Vero cells are suitable for production of influenza vaccine, but their anchorage-dependency limits their production capability. In this study adherent Vero and MDCK cells were transfected with human siat7e gene in order to convert anchorage-dependent cells to those capable of growing in suspension. Methods: Human siat7e gene was amplified with primers containing restriction sites for Xho I and Hind III and the product was cloned into pEGFP-N1 vector upstream of GFP sequence. The cells were transfected with the construct containing the siat7e gene and a medium containing G418 was used to select stably transfected cells which were then evaluated using inverted immunofluorescence microscopy. Results: Anchorage-dependent cells exhibited changes in cell-cell adhesion and cell spreading behavior following transfection. Vero cells showed a higher longevity compared to MDCK cells as viability of the latter cells declined after 50 h. Conclusion: The data showed that adherent Vero cells can successfully be converted to anchorage- independent cells capable of growing in suspension through transfection with human siat7e gene.

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Introduction: Influenza virus has several conserved peptides which have the capacity to be used as suitable candidates for appropriate and stable vaccine production against different types of influenza viruses. One of these peptides is HA2, the hemagglutinin stalk domain which mediates the membrane fusion and is conserved amongst different sub-types of influenza virus. This peptide is a good candidate for participation in vaccine structure to induce immunity and antibody production. The ensued antibody may hamper the membrane fusion and subsequently the virus propagation. Methods: The peptide sequence of HA2 from influenza virus A/Tehran/18/2010 (H1N1) was analyzed using in silico tools in order to evaluate its physicochemical properties and identification of its best immunogenic sites. The confirmed sequence was amplified and cloned into a pET28a vector and the recombinant protein was over-expressed prokaryotically and confirmed by Western blotting. Results: The bioinformatics data showed that HA2 peptide stability and immunogenicity. The generated HA2 construct was confirmed by PCR, endonuclease restriction enzyme analysis and sequencing. The expression of HA2 was confirmed by SDS-PAGE and Western blot analysis. The results on the cell lysate demonstrated the high expression of HA2 subunit of the influenza virus hemagglutinin. Conclusion: One of the disadvantages of the current flu vaccines is that they cannot produce efficient broad-spectrum cellular and humoral immune responses against all subtypes of the virus due to the genetic variation of the virus. Therefore, such a conserved protein is potentially a good candidate for production of a broad-spectrum vaccine to prevent influenza epidemics and pandemics.