B-cell receptor specific for influenza hemagglutinin and neuraminidase (BCR)

The B-cell receptor (BCR) specific for influenza hemagglutinin (HA) and neuraminidase (NA) epitopes is a specialized membrane-bound immunoglobulin complex that serves as the primary sensor for influenza virus antigens on B lymphocytes (Nature Reviews Immunology, 2018). These receptors are composed of an antigen-binding subunit (membrane immunoglobulin) and a signaling subunit (CD79A and CD79B), which together mediate the recognition of specific viral surface proteins. HA-specific BCRs typically target the globular head or the conserved stem region of the hemagglutinin protein, while NA-specific BCRs target the neuraminidase enzyme to prevent viral egress (Journal of Virology, 2019). Upon antigen engagement, the BCR initiates intracellular signaling pathways, such as the Syk/PI3K/PLC-gamma2 cascade, which drives B-cell activation, clonal expansion, and the eventual secretion of high-affinity antibodies. In clinical practice, these receptors are the fundamental targets of seasonal and universal influenza vaccines, which aim to expand the pool of memory B cells and plasma cells capable of neutralizing diverse viral strains (NIH, 2023). Furthermore, monoclonal antibodies derived from these BCR sequences, such as MEDI8852 and CR9114, are being investigated as therapeutic agents to provide immediate passive immunity against severe influenza infections (ClinicalTrials.gov, 2022).

Other names

Influenza-specific B-cell receptorHA-reactive B-cell receptorNA-reactive B-cell receptorAnti-influenza B-cell receptorSurface immunoglobulin specific for influenza

Antigen binding to the B-cell receptor (BCR) triggers the phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) within the CD79A/CD79B signaling subunits. This initiates a downstream signaling cascade involving Syk, PI3K, and PLC-gamma2, which leads to B-cell activation, clonal expansion, and differentiation into memory B cells or antibody-secreting plasma cells (Nature Reviews Immunology, 2018).