Monoclonal Antibodies to S and N SARS-CoV-2 Proteins as Probes to Assess Structural and Antigenic Properties of Coronaviruses

Abstract

Antibodies targeting the spike (S) and nucleocapsid (N) proteins of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are essential tools. In addition to important roles in the treatment and diagnosis of infection, the availability of high-quality specific antibodies for the S and N proteins is essential to facilitate basic research of virus replication and in the characterization of mutations responsible for variants of concern. We have developed panels of mouse and rabbit monoclonal antibodies (mAbs) to the SARS-CoV-2 spike receptor-binding domain (S-RBD) and N protein for functional and antigenic analyses. The mAbs to the S-RBD were tested for neutralization of native SARS-CoV-2, with several exhibiting neutralizing activity. The panels of mAbs to the N protein were assessed for cross-reactivity with the SARS-CoV and Middle East respiratory syndrome (MERS)-CoV N proteins and could be subdivided into sets that showed unique specificity for SARS-CoV-2 N protein, cross-reactivity between SARS-CoV-2 and SARS-CoV N proteins only, or cross-reactivity to all three coronavirus N proteins tested. Partial mapping of N-reactive mAbs were conducted using truncated fragments of the SARS-CoV-2 N protein and revealed near complete coverage of the N protein. Collectively, these sets of mouse and rabbit monoclonal antibodies can be used to examine structure/function studies for N proteins and to define the surface location of virus neutralizing epitopes on the RBD of the S protein.

Amperometric immunosensor developed for sensitive detection of SARS-CoV-2 spike S1 protein in combined with portable device

“…In our study, a high affinity and specificity on detection of S1 protein was achieved in the presence of CAb immobilization onto the electrode surface by using rabbit monoclonal antibody similarly to the results of earlier studies confirming the higher affinity and specificity of rabbit monoclonal antibodies [ 23 , 24 ]. By the immobilization of rabbit monoclonal antibody onto the electrode surface, the stability of immuno-complex between Cab and its target antigen occurred on the electrode surface is ensured.…”

Optical biosensors for diagnosis of COVID-19: nanomaterial-enabled particle strategies for post pandemic era

“…Monoclonal antibodies are generated from B-cells isolated from the immunized animals that are subsequently immortalized and selected for their abilities to produce single high-affinity antibodies towards well-defined epitopes. A number of monoclonal antibodies have been developed that specifically bind SARS-CoV-2 antigens [39][40][41][42]. Monoclonal antibodies, which can be generated in large qualified batches via contract research organizations, are commonly used in clinical diagnostic assays including enzyme-linked immunosorbent assays (ELISA), plaque reduction neutralization assays (PRNT), and lateral flow assays (LFA).…”

Antiviral drug design based on structural insights into the N-terminal domain and C-terminal domain of the SARS-CoV-2 nucleocapsid protein

“…In addition, many immunological studies have shown that N protein interacts with host proteins to induce immune responses or regulate the cell cycle of host cells after viral infection [15] , [16] , [17] , [18] . Many antibodies to the N protein can be detected in patients with COVID-19 to be used as a basis for diagnosis and treatment [19] , [20] . The nucleocapsid protein of coronavirus contains two main domains: the N-terminal domain (NTD) and the C-terminal domain (CTD) [21] .…”