Infection-enhancing anti-SARS-CoV-2 antibodies recognize both the original Wuhan/D614G strain and Delta variants. A potential risk for mass vaccination ?
Published:August 09, 2021DOI:https://doi.org/10.1016/j.jinf.2021.08.010
Infection-enhancing antibodies have been detected in symptomatic Covid-19
Antibody dependent enhancement (ADE) is a potential concern for vaccines
Enhancing antibodies recognize both the Wuhan strain and Delta variants
ADE of Delta variants is a potential risk for current vaccines
Vaccine formulations lacking ADE epitope are suggested
Antibody dependent enhancement (ADE) of infection is a safety concern for vaccine strategies. In a recent publication, Li et al. (Cell 184 :1-17, 2021) have reported that infection-enhancing antibodies directed against the N-terminal domain (NTD) of the SARS-CoV-2 spike protein facilitate virus infection in vitro, but not in vivo. However, this study was performed with the original Wuhan/D614G strain. Since the Covid-19 pandemic is now dominated with Delta variants, we analyzed the interaction of facilitating antibodies with the NTD of these variants. Using molecular modelling approaches, we show that enhancing antibodies have a higher affinity for Delta variants than for Wuhan/D614G NTDs. We show that enhancing antibodies reinforce the binding of the spike trimer to the host cell membrane by clamping the NTD to lipid raft microdomains. This stabilizing mechanism may facilitate the conformational change that induces the demasking of the receptor binding domain. As the NTD is also targeted by neutralizing antibodies, our data suggest that the balance between neutralizing and facilitating antibodies in vaccinated individuals is in favor of neutralization for the original Wuhan/D614G strain. However, in the case of the Delta variant, neutralizing antibodies have a decreased affinity for the spike protein, whereas facilitating antibodies display a strikingly increased affinity. Thus, ADE may be a concern for people receiving vaccines based on the original Wuhan strain spike sequence (either mRNA or viral vectors). Under these circumstances, second generation vaccines with spike protein formulations lacking structurally-conserved ADE-related epitopes should be considered.
The aim of the present study was to evaluate the recognition of SARS-CoV-2 Delta variants by infection enhancing antibodies directed against the NTD. The antibody studied is 1054 (pdb file #7LAB) which has been isolated from a symptomatic Covid-19 patient
. Molecular modelling simulations were performed as previously described
. Two currently circulating Delta variants were investigated, with the following mutational patterns in the NTD :
– G142D/E154K (B.1.617.1)
– T19R/E156G/del157/del158/A222V (B.1.617.2)