Monoclonal Antibodies to Distinct Sites on Herpes Simplex Virus (HSV) Glycoprotein D Block HSV Binding to HVEM

Abstract

HVEM (for herpesvirus entry mediator) is a member of the tumor necrosis factor receptor superfamily and mediates entry of many strains of herpes simplex virus (HSV) into normally nonpermissive Chinese hamster ovary (CHO) cells. We used sucrose density centrifugation to demonstrate that purified HSV-1 KOS virions bind directly to a soluble, truncated form of HVEM (HVEMt) in the absence of any other cell-associated components. Therefore, HVEM mediates HSV entry by serving as a receptor for the virus. We previously showed that soluble, truncated forms of HSV glycoprotein D (gDt) bind to HVEMt in vitro. Here we show that antibodies specific for gD, but not the other entry glycoproteins gB, gC, or the gH/gL complex, completely block HSV binding to HVEM. Thus, virion gD is the principal mediator of HSV binding to HVEM. To map sites on virion gD which are necessary for its interaction with HVEM, we preincubated virions with gD-specific monoclonal antibodies (MAbs). MAbs that recognize antigenic sites Ib and VII of gD were the only MAbs which blocked the HSV-HVEM interaction. MAbs from these two groups failed to coprecipitate HVEMt in the presence of soluble gDt, whereas the other anti-gD MAbs coprecipitated HVEMt and gDt. Previous mapping data indicated that site VII includes amino acids 11 to 19 and site Ib includes 222 to 252. The current experiments indicate that these sites contain residues important for HSV binding to HVEM. Group Ib and VII MAbs also blocked HSV entry into HVEM-expressing CHO cells. These results suggest that the mechanism of neutralization by these MAbs is via interference with the interaction between gD in the virus and HVEM on the cell. Group Ia and II MAbs failed to block HSV binding to HVEM yet still neutralized HVEM-mediated entry, suggesting that these MAbs block entry at a step other than HVEM binding.

Antibody-Induced Conformational Changes in Herpes Simplex Virus Glycoprotein gD Reveal New Targets for Virus Neutralization

“…(B) Structures of gD showing the receptor-binding face and the fusion activation face. mon (bind both HSV-1 and -2), react with discontinuous (38) epitopes, and block binding of gD to both receptors, HVEM and nectin-1 (28,38,40,58). Others, such as those in group VII, have virus-neutralizing activity but block binding to only one of the two receptors ( Fig.…”

“…Others, such as those in group VII, have virus-neutralizing activity but block binding to only one of the two receptors ( Fig. 1A and Table 1) (28,36,40).…”

“…In prior studies, we and others showed that virusneutralizing antibodies can be directed at HSV gD, gH/gL, or gB (6,8,36,39). Among those directed at gD, some blocked binding of gD to HVEM but not nectin-1 and others blocked gD binding to both receptors (28,40). Here we report the identification of two separate monoclonal antibodies, MC2 and MC5, that bind to gD in the presence of either HVEM or nectin-1 and do not block receptor binding to gD but effectively neutralize HSV infection.…”

Monoclonal Antibodies, Derived from Humans Vaccinated with the RV144 HIV Vaccine Containing the HVEM Binding Domain of Herpes Simplex Virus (HSV) Glycoprotein D, Neutralize HSV Infection, Mediate Antibody-Dependent Cellular Cytotoxicity, and Protect Mice from Ocular Challenge with HSV-1

“…MAbs to the receptor binding sites of other viruses, including Ebola virus (35), Epstein-Barr virus (EBV) (36), Middle East respiratory syndrome (MERS) virus (37), severe acute respiratory syndrome (SARS) coronavirus (38), influenza virus (39), poliovirus (40), and HIV (41), can potently neutralize virus infection. MAbs DL11 and E317 were previously reported to block both the nectin-1 and HVEM receptor binding sites (42)(43)(44). Thus, a vaccine that induces an antibody that blocks HSV binding to HVEM and nectin-1 might be more effective at protecting epithelial cells from infection than a vaccine that targets the HVEM binding domain of gD alone.…”

A novel glycoprotein D-specific monoclonal antibody neutralizes herpes simplex virus

“…After binding to a cell surface receptor, either HVEM or nectin-1, gD undergoes conformational changes to adopt an open conformation, which is a key step in activating the core fusion machinery of gH/gL and gB. gD is the most abundantly expressed glycoprotein on the virion, and it induces both humoral and cellular immunity and is the major stimulus of virus-neutralizing antibodies together with gB (Bender et al, 2007;Eisenberg et al, 2012;Fotouhi et al, 2008;Nicola et al, 1998;Whitbeck et al, 1999). Therefore, gD has been the predominant candidate for HSV vaccine or novel therapeutic strategies (Awasthi and Friedman, 2014;Shin and Iwasaki, 2013).…”