Localization of a Binding Site for Herpes Simplex Virus Glycoprotein D on Herpesvirus Entry Mediator C by Using Antireceptor Monoclonal Antibodies

Abstract

The human herpesvirus entry mediator C (HveC), also known as the poliovirus receptor-related protein 1 (PRR1) and as nectin-1, allows the entry of herpes simplex virus type 1 (HSV-1) and HSV-2 into mammalian cells. The interaction of virus envelope glycoprotein D (gD) with such a receptor is an essential step in the process leading to membrane fusion. HveC is a member of the immunoglobulin (Ig) superfamily and contains three Ig-like domains in its extracellular portion. The gD binding site is located within the first Ig-like domain (V domain) of HveC. We generated a panel of monoclonal antibodies (MAbs) against the ectodomain of HveC. Eleven of these, which detect linear or conformational epitopes within the V domain, were used to map a gD binding site. Among the 11 envelope glycoproteins of herpes simplex virus (HSV), glycoprotein D (gD) plays an essential role during viral entry into mammalian cells (14). gD binds specifically to one of several cell surface receptors during the pH-independent process that leads to fusion of the HSV envelope with the cell plasma membrane (13). Other essential glycoproteins such as gB and the gH-gL heterodimer also participate in the fusion event in ways that remain to be elucidated (9,35,38).Several HSV gD receptors have been identified. Herpesvirus entry mediator A (HveA; also known as HVEM and TNFRSF14) is a member of the tumor necrosis factor receptor family which binds gD and allows the entry of most HSV-1 and HSV-2 strains (25, 41). HveB (nectin-2) and HveC (nectin-1) are members of the immunoglobulin (Ig) superfamily that are closely related to the poliovirus receptor (PVR; also known as CD155) and to the newly discovered nectin-3 (8, 21, 22, 33). Whereas the activity of HveB is limited to certain HSV-2 strains and some laboratory strains of HSV-1 (rid1 and ANG) and pseudorabies virus (PRV) (20, 39), HveC allows the entry of all the HSV-1 and HSV-2 strains tested as well as PRV and bovine herpesvirus 1 (10). Poliovirus receptor does not function as an HSV receptor but can be used by PRV and bovine herpesvirus 1 (10). A specific type of heparan sulfate modified by D-glucosaminyl-3-O-sulfotransferase 3 can substitute for HveA or HveC and binds to gD to allow the entry of HSV-1 KOS into cells (34).HveB and HveC appear to be involved in cell-cell interaction and were named nectin-2 and nectin-1, respectively, according to their newly discovered function (1,19,37). In this paper, we will refer to them according to their viral usage (i.e., HveB and HveC).Recently, mutations in the HveC gene (named PVRL1 in that study) were linked to a form of cleft lip/palate-ectodermal dysplasia in humans (36).Although they have different structures, HveA and HveC bound to HSV-1 gD with similar affinity (17, 42). Using antibody competition and mutagenesis, the binding sites for HveC and HveA were mapped to common and distinct regions of gD (16,28,40). Reciprocally, the gD binding site on HveC has been localized to the first and most distal of the three Ig-like domains (or V domain) of its extr...

Prominent Role of the Ig-like V Domain intrans-Interactions of Nectins

“…Antibodies-The mAbs R1.302, CK6, and CK8 directed to the V domain of hNectin1 were described previously (25,27). The anti-PVR antibody PV.404 was described previously (28).…”

“…Recent studies based on monoclonal antibody (mAb) competition or chimeric nectin1/PVR molecules identified the C-CЈ-CЉ ␤-strands and intervening loops of the nectin1 V domain as the gD binding site. The A, B, D, E, F, and G ␤-strands do not appear to play any role in HSV entry (27,28) In this study, we investigated the mechanisms by which nectin1 mediates heterophilic interactions with nectin3 and nectin4 and trans-homophilic interactions with nectin1. Using different approaches, we found the following.…”

Structure-Based Identification of a Major Neutralizing Site in an Adenovirus Hexon

“…Antibody binding competition assays were performed as described by Krummenacher et al (14). Briefly, 20 l of the first antibody (Ab) was injected for 4 min at 5 l/min to saturate available binding sites.…”

“…Experiments were performed at room temperature on a Biacore X optical biosensor (Biacore AB). AdC68 hexon (10 g/ml), diluted in 10 mM acetate buffer, pH 4.5, was directly coupled via primary amines to a CM5 chip using a standard protocol (BIA applications handbook, Biacore AB, Uppsala, Sweden) (14) in a running buffer of PBS-0.005% Tween 20. In short, an equal mix of 0.2 M EDC [N-ethyl-NЈ-(dimethylaminopropyl carbodiimide)] and 0.5 M NHS (Nhydroxysuccinimide) was used to activate the reactive ester groups on flow cell 2 (FC2) for coupling with hexon.…”

The soluble ectodomain of herpes simplex virus gD contains a membrane-proximal pro-fusion domain and suffices to mediate virus entry

“…The gD-binding site on HVEM maps mainly to the N-terminal cysteine-rich domain 1, with a hot spot at Y23 (10,11). For nectin1, the N-terminal V domain, in particular its CCЈCЉ ridge (amino acids 64-104) is sufficient to mediate HSV entry (12)(13)(14)(15). Critical residues were located in the 69-75 region and at positions 77 and 85 (16,17).…”