Tetherin is an interferon (IFN)-inducible innate restriction factor involved in the host defense against the release of envelope viruses [
1,
2]. Based on the deduced amino acid sequence, tetherin is characterized as a type II membrane protein with a Mr of approximately 24 kDa, while its mature form is a 30-36-kDa, heterogeneously glycosylated, dimeric, type II integral membrane protein, presumably due to heterogeneity of glycosylation during post-translational modification, comprising a small cytoplasmic tail (CT) domain, a trans-membrane (TM) domain, a glycophosphatidylinositol (GPI) membrane anchor at the C-terminus, and a long disulfide-rich coiled coil structure (CC) predicted for the extracellular domain [
3,
4]. The mechanism by which different viruses counteract tetherin is distinct. To date, a number of viral proteins including Vpu and Env of HIV, Env and Nef of SIV, K5 of KSHV, Ebola GP, gM/VHS of HSV-1 and gB/gD/gH/gL of HSV-2 have been revealed to counteract the restrictive properties of tetherin [
1,
5‐
12]. Except a recent report that Ebola GP may overcome tetherin restriction by blocking an interaction between VP40 and tetherin [
13], the counteraction generally depends on the interaction between an viral antagonist and a specific domain of tetherin [
14]. For instance, HIV-1 Vpu targets the TM domain of tetherin for the subsequent antagonism of tetherin function [
1,
2,
15‐
19]; HIV-2 and tantalus SIV (SIVtan) Env interacts with the ectodomain of tetherin [
20,
21], while other SIVs employ the Nef protein to target the cytoplasmic domain of tetherin [
6,
8,
22]. The mechanisms underlying HIV-1 counteracts tetherin have been intensively investigated, but less attention has been paid to understanding those mediated by other viruses.
Herpes simplex virus 2 (HSV-2) is a DNA virus sexually transmitted and causes persistent infection that cannot be eliminated [
23]. HSV-2 is the leading cause of genital ulcer disease (GUD) throughout the world and associated with human immunodeficiency virus 1 (HIV-1) acquisition [
24‐
28]. HSV-2 transmission occurs via cell-free and direct cell-to-cell spread [
29]. The HSV-2 glycoprotein D (gD), a major component of the virion envelope, was previously revealed to be essential for viral fusion and plays an important role in the cell-to-cell spread of the virus in permissive cells [
30,
31].
Our previous study has revealed that tetherin functions as a restriction factor to inhibit HSV-2 release and that several glycoproteins including gD downregulate the expression of tetherin [
11]. In this study, we investigated whether tetherin restricts the cell-to-cell spread of HSV-2 and the mechanisms underlying HSV-2 gD mediated antagonism of tetherin.