Distinct Cell Tropism and Infection Induced Host Gene Expression in Human Nasal Epithelial Cell Cultures Infected with The Influenza B Virus Victoria and Yamagata Lineages

Understanding Influenza B virus infections is of critical importance in our efforts to control severe influenza-related disease. Until 2020, two genetic lineages of influenza B virus Yamagata and Victoria, heavily circulated in the population. These lineages are antigenically distinct but differences in virus replication or the induction of host cell responses after infection have not been carefully studied. Recent IBV clinical isolates of both lineages were obtained from influenza surveillance efforts of the Johns Hopkins Center of Excellence in Influenza Research and Surveillance and characterized in vitro. B/Victoria and B/Yamagata clinical isolates were recognized less efficiently by serum from influenza-vaccinated individuals in comparison to the vaccine strains. B/Victoria lineages formed smaller plaques on MDCK cells compared to B/Yamagata, but growth curves on MDCK-SIAT and primary human nasal epithelial cell (hNEC) cultures showed no differences in infectious virus production. While ciliated epithelial cells were the dominant cell type infected by both lineages, B/Victoria lineages had a slight preference for MUC5AC-positive cells, while B/Yamagata lineages infected more basal cells. Finally, while both lineages induced a strong interferon response 48 hours after infection of hNEC cultures, the B/Victoria lineages showed a much stronger induction of interferon related signaling pathways compared to B/Yamagata. This demonstrates that the two influenza B virus lineages differ not only in their antigenic structure but in their replication and ability to dampen host innate immune responses.