A potent and protective human neutralizing antibody targeting a novel vulnerable site of Epstein-Barr virus

Abstract

Epstein-Barr virus (EBV) is associated with a range of epithelial and B cell malignancies as well as autoimmune disorders, for which there are still no specific treatments or effective vaccines. Here, we isolate EBV gH/gL-specific antibodies from an EBV-infected individual. One antibody, 1D8, efficiently neutralizes EBV infection of two major target cell types, B cells and epithelial cells. In humanized mice, 1D8 provides protection against a high-dose EBV challenge by substantially reducing viral loads and associated tumor burden. Crystal structure analysis reveals that 1D8 binds to a key vulnerable interface between the D-I/D-II domains of the viral gH/gL protein, especially the D-II of the gH, thereby interfering with the gH/gL-mediated membrane fusion and binding to target cells. Overall, we identify a potent and protective neutralizing antibody capable of reducing the EBV load. The novel vulnerable site represents an attractive target that is potentially important for antibody and vaccine intervention against EBV infection.

Immunization with a self-assembling nanoparticle vaccine displaying EBV gH/gL protects humanized mice against lethal viral challenge

“…Immunocompromised mice engrafted with human hematopoietic stem cells develop human B cells that can become infected by EBV and are used as an in vivo model of EBV infection (Fujiwara and Nakamura, 2020; Münz, 2017). This model has been used to evaluate the ability of monoclonal, or polyclonal antibodies elicited by either vaccination or infection to protect against controlled viral challenge (Cui et al, 2021; Kim et al, 2021; Singh et al ., 2020; Zhu et al ., 2021). Having established that gH/gL nanoparticles display superior immunogenicity, we sought to assess whether the antibodies they elicit confer protection against EBV challenge in this model.…”

“…Thus, relative to monomeric gH/gL, the gH/gL 60-mer may have elicited high titers of less potent anti-gH/gL antibodies like CL40 and CL59. Alternatively, the immunogens may have elicited antibodies targeting other potently neutralizing epitopes on gH/gL such as the one defined by the recently identified 1D8 mAb or other yet to be identified epitopes (Zhu et al ., 2021). Gaining a better understanding of the epitopes on gH/gL that are targeted by neutralizing and non-neutralizing antibodies elicited by natural infection or immunization through the isolation and characterization of monoclonal antibodies would enable rational gH/gL vaccine design that could further enhance neutralizing titers when combined with multimeric antigen display.…”

“…The 769B10 mAb also neutralizes EBV infection of both cell types and binds to an epitope that overlaps with AMMO1, confirming this is a critical site of vulnerability on EBV (Bu et al ., 2019). Passive transfer of AMMO1 severely limits viral infection following high-dose experimental EBV challenge in humanized mice and protects rhesus macaques against oral challenge with RhLCV if present at adequate levels at the time of challenge (Singh et al, 2020; Zhu et al ., 2021). These studies provide proof of concept that anti-gH/gL antibodies can protect against EBV infection and indicate that a gH/gL-based vaccine capable of eliciting AMMO1-like antibodies could prevent oral transmission of the virus.…”

“…Anti-gH/gL antibodies account for most serum antibodies that neutralize EBV infection of epithelial cells, but only a small fraction of antibodies that neutralize infection of B cells (Bu et al ., 2019). Only a handful of anti-gH/gL monoclonal antibodies (mAbs) have been identified, all of which neutralize EBV infection of epithelial cells with comparable potency, but most have weak, or no neutralizing activity against EBV infection of B cells (Chesnokova and Hutt-Fletcher, 2011; Li et al, 1995; Molesworth et al ., 2000; Sathiyamoorthy et al, 2016; Sathiyamoorthy et al, 2017; Snijder et al, 2018; Zhu et al, 2021). We previously described the isolation and characterization AMMO1, an anti-gH/gL monoclonal antibody (mAb) which potently neutralizes EBV infection of epithelial cells and B cells in vitro by binding to a discontinuous epitope on gH/gL (Snijder et al ., 2018).…”

A bivalent Epstein-Barr virus vaccine induces neutralizing antibodies that block infection and confer immunity in humanized mice

“…The failure of an EBV gp350 vaccine to achieve sterilizing immunity in a clinical trial ( 12 ) suggests that a second component is advisable in a next-generation vaccine. Monoclonal antibodies (mAbs) to the gH/gL complex protect against EBV infection in humanized mice ( 32 , 33 ). Anti-gH/gL mAbs, such as AMMO1, have been shown to induce sterilizing immunity in NHPs challenged with the rhesus homolog of EBV and are more potent in inhibiting EBV infection than anti-gp350 mAbs, such as 72A1 ( 32 ).…”