Development of high-growth influenza H7N9 prepandemic candidate vaccine viruses in suspension MDCK cells

Abstract

Background: Influenza vaccine manufacturers traditionally use egg-derived candidate vaccine viruses (CVVs) to produce high-yield influenza viruses for seasonal or pandemic vaccines; however, these egg-derived CVVs need an adaptation process for the virus to grow in mammalian cells. The low yields of cell-based manufacturing systems using egg-derived CVVs remain an unsolved issue. This study aimed to develop high-growth cell-derived CVVs for MDCK cell-based vaccine manufacturing platforms. Methods: Four H7N9 CVVs were generated in characterized Vero and adherent MDCK (aMDCK) cells. Furthermore, reassortant viruses were amplified in adherent MDCK (aMDCK) cells with certification, and their growth characteristics were detected in aMDCK cells and new suspension MDCK (sMDCK) cells. Finally, the plaque-forming ability, biosafety, and immunogenicity of H7N9 reassortant viruses were evaluated.Results: The HA titers of these CVVs produced in proprietary suspension MDCK (sMDCK) cells and chicken embryos were 2-to 8-fold higher than those in aMDCK cells. All H7N9 CVVs showed attenuated characteristics by trypsindependent plaque assay and chicken embryo lethality test. The alum-adjuvanted NHRI-RG5 (derived from the fifth wave H7N9 virus A/Guangdong/SP440/2017) vaccine had the highest immunogenicity and cross-reactivity among the four H7N9 CVVs. Finally, we found that AddaVax adjuvant improved the cross-reactivity of low pathogenic H7N9 virus against highly pathogenic H7N9 viruses. Conclusions:Our study indicates that cell-derived H7N9 CVVs possessed high growth rate in new sMDCK cells and low pathogenicity in chicken embryo, and that CVVs generated by this platform are also suitable for both cell-and egg-based prepandemic vaccine production.

Development and Evaluation of Vero Cell-Derived Master Donor Viruses for Influenza Pandemic Preparedness

“…To evaluate the immunogenicity of Vero cell-derived H7N9 antigens (rRG268-vB5 and rRG56B-vB5), mice received two doses of inactivated-whole-virus antigens (0.2 μg with 300 μg of alum adjuvant) two weeks apart, and another two groups of mice immunized with MDCK cell-derived H7N9 antigens (RG268 and NHRI-RG4, an MDCK cell-derived CVV from NHRI carrying HA and NA genes from A/Hong Kong/125/2017 [ 18 ]) as a comparison. In evaluating the homologous antibody response to the first wave H7N9 antigens, the Vero cell-derived antigens (rRG268-vB5) elicited a slightly lower HI antibody response than MDCK cell-derived antigen (RG268) (HI GMT: 253.98 vs. 507.97).…”

Construction of a peacock immortalized fibroblast cell line for avian virus production

“…At present, MDCK cells are widely used to produce virus vaccines ( Kim et al, 2018 ; Tzeng et al, 2020 ; Bissinger, et al, 2021 ). Although the safety of vaccines produced by MDCK has been evaluated in mice and other species, the efficacy, and safety of virus vaccines for the prevention and treatment of avian species are still unclear ( Garcia and Zavala, 2019 ; Ganguly et al, 2020 ; Wang et al, 2020 ; Wang et al, 2021 ).…”

Current Opinion in LAIV: A Matter of Parent Virus Choice

“…Such vaccines may demonstrate increased effectiveness compared to conventional egg-derived vaccines. A similar approach has already been described in the literature for IIV [ 124 ]. In the future, cell-derived genetically engineered LAIV based on cell-derived viruses, possessing all critical biological features, may replace the conventional time-consuming, labor-intensive egg-based influenza vaccine production technology.…”