Nectin4 restricts pseudorabies virus infection by blocking gD-Nectin1 interaction

(PRV), which causes Aujeszky's disease (AD), primarily infects swine but has zoonotic potential and can infect multiple species, including humans. Upon infection, interferons (IFNs) trigger the expression of hundreds of interferon-stimulated genes (ISGs), thereby establishing a robust cellular antiviral state. However, ISGs exhibiting anti-alphaherpesvirus activity have not yet been fully characterized. Here, we perform an unbiased screen of 268 ISGs and identify Nectin4, also known as PVRL4, as a potent antiviral ISG against alphaherpesvirus, including herpes simplex virus (HSV). Mechanistically, Nectin4 inhibits viral internalization into host cells, in which the IgV domain plays a critical role. Specifically, Nectin4 interacts with the viral gD protein through this domain, thereby inhibiting the interaction between gD and viral receptor, Nectin1, and blocking gD-mediated viral entry. Together, our data identify a previously unrecognized function of Nectin4 in host anti-alphaherpesvirus immunity and highlight a novel cellular barrier that restricts alphaherpesvirus infection. IMPORTANCE: Interferon-stimulated genes (ISGs) are the major mediators of the host antiviral innate immunity, yet most remain functionally uncharacterized against alphaherpesviruses. Here, we identify interferon-stimulated Nectin4 (PVRL4) as a potent alphaherpesvirus restriction factor. By directly engaging the viral glycoprotein D (gD) and blocking its interaction with the entry receptor Nectin1, Nectin4 suppresses viral internalization. These findings broaden our understanding of the host-alphaherpesvirus interaction and highlight Nectin4 as a potential target for antiviral intervention against alphaherpesviruses.