Stability of vaccine strains of seasonal live attenuated influenza vaccines when adapted to MDCK cell culture
Introduction. Currently, the vast majority of influenza vaccines in the world are produced using developing chicken embryos as substrate, but there is an urgent necessity for transferring vaccine production to continuous cell lines, which would ensure uninterrupted production during an avian influen...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | Russian |
| Published: |
Central Research Institute for Epidemiology
2025-07-01
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| Series: | Журнал микробиологии, эпидемиологии и иммунобиологии |
| Subjects: | |
| Online Access: | https://microbiol.crie.ru/jour/article/viewFile/18876/1608 |
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| Summary: | Introduction. Currently, the vast majority of influenza vaccines in the world are produced using developing chicken embryos as substrate, but there is an urgent necessity for transferring vaccine production to continuous cell lines, which would ensure uninterrupted production during an avian influenza pandemic and also allow the vaccine to be administered to individuals with chicken protein allergies. When vaccine strains of live attenuated influenza vaccine (LAIV) grow in mammalian cells, adaptation mutations can occur that may affect the antigenic and immunogenic properties of the vaccine.
The aim of the study is to investigate the biological properties of vaccine strains of LAIV subtypes A/H1N1 and A/H3N2, produced by the classical reassortment in eggs, when adapted to Madin–Darby canine kidney (MDCK) cell culture.
Materials and methods. In current study, LAIV strains A/17/California/2009/38 (H1N1pdm09) and A/17/Texas/12/30 (H3N2) were used. These viruses were passaged on MDCK 5 times and the growth properties of the isolated clones by the plaque assay were analyzed in vitro and in vivo, also immunogenicity, cross-reactivity and protective efficacy were estimated on a mouse model, as well as using hyperimmune rat sera. Experimental series of LAIV strains A/17/Bolivia/2013/6585 (H1N1), A/17/Switzerland/2013/1 (H3N2) and B/60/Phuket/2013/26 were produced on MDCK cells at the Vector State Research Center of Virology and Biotechnology. The surface protein genes of monovalent vaccines were sequenced, and the mutations in HA and NA were identified and compared between adaptation to MDCK culture in laboratory and industrial conditions.
Results. Sequencing of surface antigens of MDCK-adapted variants of the A/H1N1 virus revealed adaptation mutations in the hemagglutinin molecule N156D (HA1 subunit) and A44V (HA2 subunit), which enhanced the replicative properties of the H1N1 vaccine strain in MDCK cells. The study of this MDCK-adapted variant in a mouse experiment showed no effect of the detected mutations on the immunogenic and protective properties of the vaccine. Adaptation of the H3N2 vaccine strain to MDCK cells resulted in a significantly higher number of substitutions in the HA molecule compared to the H1N1 virus, and it was shown that the Y85E and N154K mutations in HA2 are critical for virus multiplication in cell culture, and the set of mutations P215T in HA1 and W92G, D160H in HA2 gave the vaccine strain a significant advantage for growth in MDCK cells, which can be effectively used in the production of cell-based LAIVs.
Discussion. The study of the MDCK cell-produced series of LAIVs showed the presence of adaptation mutations in the hemagglutinin molecule of the H1N1 (K116E in the HA2 subunit) and H3N2 (S219Y and N246K in the HA1 subunit) strains. It is important to note that all the adaptation mutations studied did not affect the antigenicity of the vaccine strains.
Conclusion. In general, the data obtained in the course of the study indicate the feasibility of producing a culture-based live attenuated influenza vaccine from vaccine strains prepared by classical reassortment in eggs. |
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| ISSN: | 0372-9311 2686-7613 |