Impact of Influenza Virus Adaptation Status on HAN-Glycosylation Patterns in Cell Culture-Based Vaccine Production

The highly abundant and strongly immunogenic influenza envelope glycoprotein hemagglutinin (HA) represents the main component of influenza vaccines. Human influenza vaccines are typically produced in embryonated chicken eggs. In addition, cell culture-derived vaccine production systems are currently being established. Since characteristics of glycoproteins such as the HA can be significantly influenced by N-glycosylation, the impact of host cells considered for vaccine manufacturing needs to be addressed. In this study MDCK cell-derived influenza A/PR/8/34 (H1N1) virus was adapted over four passages in AGE1.CR.pIX-cells. HA N-glycosylation patterns (normalized capillary electropherograms) were determined and analyzed using capillary gel electrophoresis with laser-induced fluorescence detection (each peak represents at least one distinct N-glycan structure). During the adaptation to AGE1.CR.pIX-cells, virus titers 24 hours postinfection improved. HA N-glycosylation patterns of MDCK and AGE1.CR.pIX-derived virus particles differed significantly after the first adaptation step. This clearly suggests that the structure of the viral antigens is strongly influenced by the host cell. Furthermore, AGE1.CR.pIX-derived antigens showed a tendency toward small glycans. Differences between glycan patterns of the four successive passages in AGE1.CR.pIX cell were minor; only low variability in relative peak height was noted in the HA N-glycosylation pattern.