B-cell receptor specific for SARS-CoV-2 nucleocapsid protein (BCR-N)

The B-cell receptor (BCR) specific for SARS-CoV-2 nucleocapsid (N) protein is a membrane-bound immunoglobulin complex on B lymphocytes that recognizes and binds to the viral nucleocapsid antigen. The N protein is a highly abundant and conserved structural protein of SARS-CoV-2, playing a vital role in viral RNA packaging and replication. Recognition of N-protein epitopes by these BCRs is a hallmark of the host's adaptive immune response, triggering B-cell activation, clonal expansion, and the subsequent secretion of anti-N antibodies. Although these antibodies are typically non-neutralizing due to the internal location of the N protein within the virion, they are essential diagnostic markers for identifying past SARS-CoV-2 infection. These BCRs may also contribute to viral control through non-neutralizing effector mechanisms such as antibody-dependent cellular phagocytosis or by modulating T-cell responses. Interactions with drugs primarily involve N-protein-based vaccine candidates, such as Ad5-N or mRNA-N, which are designed to stimulate these BCRs to elicit a robust and durable immune response. Furthermore, the high conservation of N-protein epitopes makes these BCRs a significant focus for the development of pan-coronavirus vaccines and sensitive serological assays.

Other names

Anti-N B-cell receptorSARS-CoV-2 N-specific BCRNucleocapsid-specific B-cell receptorAnti-SARS-CoV-2 nucleocapsid BCR

Antigen binding to the B-cell receptor (BCR) triggers the phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) by Src-family kinases, initiating a signaling cascade through Syk, PLC-gamma2, and PI3K that leads to B-cell activation, proliferation, and differentiation into antibody-secreting plasma cells.