A Strategy to Detect Emerging Non-Delta SARS-CoV-2 Variants with a Monoclonal Antibody Specific for the N501 Spike Residue

Abstract

Efforts to control SARS-CoV-2 have been challenged by the emergence of variant strains that have important implications for clinical and epidemiological decision making. Four variants of concern (VOCs) have been designated by the Centers for Disease Control and Prevention (CDC), namely, B.1.617.2 (delta), B.1.1.7 (alpha), B.1.351 (beta), and P.1 (gamma), although the last three have been downgraded to variants being monitored (VBMs). VOCs and VBMs have shown increased transmissibility and/or disease severity, resistance to convalescent SARS-CoV-2 immunity and antibody therapeutics, and the potential to evade diagnostic detection. Methods are needed for point-of-care (POC) testing to rapidly identify these variants, protect vulnerable populations, and improve surveillance. Antigen-detection rapid diagnostic tests (Ag-RDTs) are ideal for POC use, but Ag-RDTs that recognize specific variants have not yet been implemented. Here, we describe a mAb (2E8) that is specific for the SARS-CoV-2 spike protein N501 residue. The 2E8 mAb can distinguish the delta VOC from variants with the N501Y meta-signature, which is characterized by convergent mutations that contribute to increased virulence and evasion of host immunity. Among the N501Y-containing mutants formerly designated as VOCs (alpha, beta, and gamma), a previously described mAb, CB6, can distinguish beta from alpha and gamma. When used in a sandwich ELISA, these mAbs sort these important SARS-CoV-2 variants into three diagnostic categories, namely, (1) delta, (2) alpha or gamma, and (3) beta. As delta is currently the predominant variant globally, they will be useful for POC testing to identify N501Y meta-signature variants, protect individuals in high-risk settings, and help detect epidemiological shifts among SARS-CoV-2 variants.

Recombinant Protein Micelles to Block Transduction by SARS-CoV-2 Pseudovirus

“…PVs are essentially liposomes with the SARS-CoV-2 Spike S1 protein at the membrane, making them antigenically alike to the wild-type virus . PVs have a second-generation lentiviral core containing a green fluorescence protein (GFP) gene, which is expressed upon transduction . PVs have been proven to serve as a viable, non-replicating model for testing transductions by dengue, zika, and SARS-CoV-2. − 293T-hsACE2 cells express ACE2 receptors and can be transduced by PVs via ACE2-mediated endocytosis and/or via virus-cell membrane fusion; these cells were thus used as the in vitro cell model.…”

The structure of the RBD–E77 Fab complex reveals neutralization and immune escape of SARS-CoV-2

“…In contrast, the CDRL1 loops from CC12.1, CB6 and B38 contact the 'mesa' region of RBD less tightly (Fig. 5a) and therefore are resistent to the N501Y mutation to some extent (Puligedda et al, 2021;Upadhyay et al, 2021;Ray et al, 2022). Secondly, the orientation of E77 that engages RBD is rotated almost 90 clockwise from that of CC12.1, CB6 and B38 (Fig.…”

Application of the Nicoya OpenSPR to Studies of Biomolecular Binding: A Review of the Literature from 2016 to 2022

“…Researchers have used this technique to assess the binding affinity and kinetics of potential new therapeutics and affinity reagents, to study aggregation, to perform competition studies or inhibition assays, and other applications. OpenSPR has been leveraged to study diverse biochemical questions, including critical problems in human health such as Alzheimer’s disease (AD) [ 43 , 44 , 45 , 46 ], non-small cell lung cancer (NSCLC) [ 47 , 48 , 49 , 50 , 51 ], and COVID-19 [ 34 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ]. This paper provides the first comprehensive review of the literature reporting the use of the OpenSPR.…”