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BREAKING NEWS
Source: ADE and Delta Variant  Aug 13, 2021  2 years, 8 months, 4 days, 5 hours, 16 minutes ago

BREAKING! French Study Published In Journal Of Infections Claims That ADE Or Antibody Dependent Enhancement Is Occurring In Delta Variant Infections!

BREAKING! French Study Published In Journal Of Infections Claims That ADE Or Antibody Dependent Enhancement Is Occurring In Delta Variant Infections!
Source: ADE and Delta Variant  Aug 13, 2021  2 years, 8 months, 4 days, 5 hours, 16 minutes ago
A new study by French researchers from Aix-Marseille Université has alarmingly found that ADE or antibody dependent enhancement is indeed occurring in infections with the SARS-CoV-2 Delta variant.

 
The study findings were peer reviewed and published in the Journal of Infections. https://www.journalofinfection.com/article/S0163-4453(21)00392-3/fulltext
 
ADE or antibody dependent enhancement (ADE) of infection is a safety concern for vaccine strategies.
 
A misleading earlier study 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. https://www.sciencedirect.com/science/article/pii/S009286742100756X
 
This study however was performed with the original Wuhan/D614G strain.
 
Importantly since the COVID-19 pandemic is now dominated with Delta variants, the study team analyzed the interaction of facilitating antibodies with the NTD of these variants.
 
Utilizing molecular modeling approaches, the team showed that enhancing antibodies have a higher affinity for Delta variants than for Wuhan/D614G NTDs.
 
The study team demonstrated 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 de-masking of the receptor binding domain. As the NTD is also targeted by neutralizing antibodies, the study data suggest that the balance between neutralizing and facilitating antibodies in vaccinated individuals is in favor of neutralization for the original Wuhan/D614G strain.
 
Alarmingly, 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.
 
Hence antibody dependent enhancement or 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 objective 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 modeling simulations were performed as previously described
2. 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)
 
Each mutational pattern was introduced in the original Wuhan/D614G strain, submitted to energy minimization, and then tested for antibody binding.
 
The energy of inte raction (ΔG) of the reference pdb file #7LAB (Wuhan/D614G strain) in the NTD region was estimated to -229 kJ/mol−1. In the case of Delta variants, the energy of interaction was raised to -272 kJ.mol−1 (B.1.617.1) and -246 kJ.mol−1 (B.1.617.2).
 
Hence it was found that these infection enhancing antibodies not only still recognize Delta variants but even display a higher affinity for those variants than for the original SARS-CoV-2