Folate Receptor Alpha and Caveolae Are Not Required for Ebola Virus Glycoprotein-Mediated Viral Infection

AUTOR(ES)
FONTE

American Society for Microbiology

RESUMO

Folate receptor alpha (FRα) has been described as a factor involved in mediating Ebola virus entry into cells (6). Furthermore, it was suggested that interaction with FRα results in internalization and subsequent viral ingress into the cytoplasm via caveolae (9). Descriptions of cellular receptors for Ebola virus and its entry mechanisms are of fundamental importance, particularly with the advent of vectors bearing Ebola virus glycoprotein (GP) being utilized for gene transfer into cell types such as airway epithelial cells. Thus, the ability of FRα to mediate efficient entry of viral pseudotypes carrying GP was investigated. We identified cell lines and primary cell types such as macrophages that were readily infected by GP pseudotypes despite lacking detectable surface FRα, indicating that this receptor is not essential for Ebola virus infection. Furthermore, we find that T-cell lines stably expressing FRα are not infectible, suggesting that FRα is also not sufficient to mediate entry. T-cell lines lack caveolae, the predominant route of FRα-mediated folate metabolism. However, the coexpression of FRα with caveolin-1, the major structural protein of caveolae, was not able to rescue infectivity in a T-cell line. In addition, other cell types lacking caveolae are fully infectible by GP pseudotypes. Finally, a panel of ligands to and soluble analogues of FRα were unable to inhibit infection on a range of cell lines, questioning the role of FRα as an important factor for Ebola virus entry.

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