Neutralizing Monoclonal Antibodies Inhibit SARS-CoV-2 Infection through Blocking Membrane Fusion

Abstract

The spike (S) protein on the surface of SARS-CoV-2 mediates receptor binding and virus-host cell membrane fusion during virus entry. Many neutralizing antibodies (nAbs), which targeted the receptor binding domain (RBD) of S protein, lost the neutralizing activity against the newly emerging SARS-CoV-2 variants with sequence mutations at the RBD.

Simultaneous detection of antibody responses to multiple SARS-CoV-2 antigens by a Western blot serological assay

“…In the previous study (Li et al 2022 ), we have found that the S2-specific mAbs S2-4D, S2-5D, S2-8D, and S2-4A, which recognized the key residues of E1144, F1148, L1152, and F1156 within the epitope peptide S(1144–1156) and exhibited strong SARS-CoV-2 neutralizing activities. Here, we showed that the COVID-19 patient serum (P3: day 15) also exhibited cross-reactivity to S(1127–1167) (Fig.…”

“…More importantly, our data showed that the COVID-19 patient serum (P3: day 15) seemed to have a unique antibody profile against the S(1127–1167) fragment. The detailed epitope mapping experiments performed by the additional mWBS assay further demonstrated that the antibodies in the patient 3 (day 15) serum sample have the major binding epitopes at the residues F1148, K1149, L1152, Y1155, and F1156, which are very similar with several S2-specific SARS-CoV-2 neutralizing antibodies (Li et al 2022 ; Pinto et al 2021 ; Sauer et al 2021 ; Zhou et al 2022 ). Notably, patient 3 (day 15) serum sample also performed very strong SARS-CoV-2 neutralizing activity (Fig.…”

“…The gene sequence encoding for the S(732–894), S(816–855), S(895–1041), S(909–988), S(1042–1167), S(1168–1208), S(1042–1126), or S(1127–1167) was respectively subcloned into the pET30a vector (Novagen, Merck Group) with a C-terminal His-tag and an additional N-terminal superfolder GFP (sfGFP) fusion tag (Pedelacq et al 2006 ). The plasmid construction of the sfGFP-CD proteins with a series of individual alanine substitutions at the residues 1144–1157 was described in the previous study (Li et al 2022 ).…”

Antibody-mediated immunity to SARS-CoV-2 spike

“…6 C), which may facilitate its greater neutralizing potency ( Li, Chen, et al, 2022 ). In any case, after binding to SH, it is thought these mAbs then sterically “jam” S2 from folding back on itself via interactions between HR1 and SH/HR2, preventing 6-HB formation, and thus membrane fusion ( Hurlburt et al, 2022 ; Li, Chao, et al, 2022 ; Li, Chen, et al, 2022 ; Pinto et al, 2021 ; Zhou, Yuan, et al, 2022 ). Indeed, S2P6 potently inhibited cell-cell syncytium formation in SARS-CoV-2 spike-expressing Vero-E6 cells exposed to S2E12, which triggers fusogenic rearrangements by mimicking ACE2 binding ( Pinto et al, 2021 ).…”

How to Evaluate COVID-19 Vaccine Effectiveness—An Examination of Antibody Production and T-Cell Response

“…Although both types of antibodies bind to the viruses, only neutralizing antibodies prevent cell infection. Epitopes of neutralizing antibodies in the spike glycoprotein are located in the N-terminal domain of the S1 subunit (linear and quaternary epitopes in the N-terminal domain) and in the S2 subunit [ 10 , 11 , 12 ]. The SARS-CoV-2 virus comprises several structural proteins including spike protein (S), envelop protein (E), membrane protein (M), and nucleocapsid protein (N).…”