Sooksawasdi Na Ayudhya, S.

bioRxiv2025

Sialic acid-containing glycolipids extend the receptor repertoire of Enterovirus-D68

Enterovirus D68 (EV-D68) emerged as a pathogen of increasing health concern globally, particularly due to its association with outbreaks of severe respiratory diseases and acute flaccid myelitis (AFM) in children. Knowledge regarding the tissue tropism and pathogenesis of EV-D68 within the respiratory tract and central nervous system remains limited, primarily due to an incomplete understanding of the host factors that facilitate EV-D68 entry into host cells. Several cellular receptors involved in EV-D68 infections have been identified, including ICAM-5, sialylated glycoproteins, and heparan sulfate (HS). Here, we investigate the receptor requirement of a panel of EV-D68 strains covering all clades focusing on HS and sialosides utilizing glycan arrays. We found that all EV-D68 strains binding to HS harbour a cell culture adaptative substitution in the structural protein VP1 at position 271 which changes the amino acid into a positive charged one. Glycan array analyses revealed that EV-D68 strains either prefer 2,6-linked sialic acids presented on N-glycans, 2,8 linked sialic acids on gangliosides, or both. Inhibition of glycolipid biosynthesis or multivalent glycolipid mimics confirmed that ganglioside structures serve as entry receptors for certain EV-D68 strains. Lastly, we examined whether EV-D68 strains that bind to HS or glycolipids require different uncoating mechanisms. Bafilomycin A1 minimally affected cell entry of HS-binding EV-D68 strains B2/039 and B2/947 and the ganglioside preferring B1/2013 other viruses were strongly inhibited. Together, we identified that EV-D68 strains can use disialoglycolipids as novel receptors and that different EV-D68 strains show a promiscuous sialic acid binding repertoire.

microbiology↗

bioRxiv2022

The potential role of human immune cells in the systemic dissemination of enterovirus-D68

Enterovirus-D68 (EV-D68) often causes mild respiratory infections, but can also cause severe respiratory infections and extra-respiratory complications, including acute flaccid myelitis (AFM). Systemic dissemination of EV-D68 is crucial for the development of extra-respiratory diseases, but it is currently unclear how EV-D68 viremia occurs. We hypothesize that immune cells contribute to the systemic dissemination of EV-D68, as this is a mechanism commonly used by other enteroviruses. Therefore, we investigated the susceptibility and permissiveness of human primary immune cells for different EV-D68 isolates. In human peripheral blood mononuclear cells (PBMC) inoculated with EV-D68, only B cells were susceptible but virus replication was limited. However, B cell-rich cultures, such as Epstein-Barr virus-transformed B-lymphoblastoid cell line (BLCL) and primary lentivirus-transduced B cells, were productively infected. In BLCL, neuraminidase treatment to remove 2,6- and 2,3-linked sialic acids resulted in a significant decrease of EV-D68 infected cells, suggesting that sialic acids are the functional receptor on B cells. Subsequently, we showed that dendritic cells (DCs), particularly immature DCs, are susceptible and permissive for EV-D68 infection and that they can spread EV-D68 to autologous BLCL. Altogether, our findings suggest that immune cells, especially B cells and DCs, play an important role in the development the systemic dissemination of EV-D68 during an infection, which is an essential step towards the development of extra-respiratory complications. Author summaryEnterovirus D68 (EV-D68) is an emerging respiratory virus that has caused outbreaks worldwide since 2014. EV-D68 infects primarily respiratory epithelial cells and the infection commonly results in mild respiratory diseases. However, EV-D68 infection is also associated with complications outside the respiratory tract, including a polio-like paralysis. Despite the severity of these extra-respiratory complications, it is unclear how EV-D68 is able to spread outside the respiratory tract and infect other organs, like the central nervous system (CNS). To understand this, we investigated if immune cells play a role in the extra-respiratory spread of EV-D68. We showed that EV-D68 can infect and replicate in specific immune cells, i.e. B cells and dendritic cells (DCs), and that the virus can be transferred from DCs to B cells. Our findings suggest that lymphoid tissues, which harbor many immune cells, can be a secondary replication site for EV-D68, from where virus is released in the circulation. Our data reveal the importance of immune cells in the systemic spread of EV-D68, which is essential for infection of extra-respiratory tissues. Intervention strategies that prevent EV-D68 infection of immune cells will therefore potentially prevent virus spread from the respiratory tract to other organs.

microbiology↗