Currently, the majority of commercial recombinant therapeutic proteins are produced in nonhuman expression systems. Human cells are capable of producing recombinant proteins with post‐translational modifications that are more similar to native proteins which reduce immunogenicity. This article describes the potential of the human cell lines Sk‐Hep‐1, HKB‐11, and Huh‐7, cultured in serum‐free suspension conditions, to produce a complex recombinant glycoprotein, human erythropoietin (EPO). Recombinant cell lines were generated by lentiviral transduction and sorted by flow cytometry. All the recombinant cells presented high‐specific cell growth rates and a high level of rhEPO production. Maximum rhEPO concentrations achieved by Sk‐Hep‐1, HKB‐11, and Huh‐7 cells were 112.5 μg/mL, 112.7 μg/mL, and 571 μg/mL, respectively. The levels of rhEPO production by Huh‐7 cells were higher than the levels commonly reported in the literature for serum‐free suspension cultures. The rhEPO produced demonstrated biological activity measured through in vitro differentiation of CD34+ cells. In view of this, we demonstrate that Sk‐Hep‐1, HKB‐11, and Huh‐7 cell lines have good characteristics to be used as host cells for the production of complex recombinant glycoproteins, with special emphasis on Huh‐7 due to enhanced EPO production.
From a country with one of the highest SARS-CoV-2 morbidity and mortality rates, Brazil has implemented one of the most successful vaccination programs. Brazil’s first model city vaccination program was performed by the CoronaVac vaccine (Sinovac Biotech) in the town of Serrana, São Paulo State. To evaluate the vaccination effect on the SARS-CoV-2 molecular dynamics and clinical outcomes, we performed SARS-CoV-2 molecular surveillance on 4375 complete genomes obtained between June 2020 and April 2022 in this location. This study included the period between the initial SARS-CoV-2 introduction and during the vaccination process. We observed that the SARS-CoV-2 substitution dynamics in Serrana followed the viral molecular epidemiology in Brazil, including the initial identification of the ancestral lineages (B.1.1.28 and B.1.1.33) and epidemic waves of variants of concern (VOC) including the Gamma, Delta, and, more recently, Omicron. Most probably, as a result of the immunization campaign, the mortality during the Gamma and Delta VOC was significantly reduced compared to the rest of Brazil, which was also related to lower morbidity. Our phylogenetic analysis revealed the evolutionary history of the SARS-CoV-2 in this location and showed that multiple introduction events have occurred over time. The evaluation of the COVID-19 clinical outcome revealed that most cases were mild (88.9%, 98.1%, 99.1% to Gamma, Delta, and Omicron, respectively) regardless of the infecting VOC. In conclusion, we observed that vaccination was responsible for reducing the death toll rate and related COVID-19 morbidity, especially during the gamma and Delta VOC; however, it does not prevent the rapid substitution rate and morbidity of the Omicron VOC.
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