Human B-cell receptor specific for influenza hemagglutinin (HA-specific BCR)

Human B-cell receptors (BCRs) specific for influenza hemagglutinin are the primary sensors on B lymphocytes that recognize the hemagglutinin (HA) protein of the influenza virus. These receptors are composed of a membrane-bound immunoglobulin that provides antigen specificity and a signaling subunit (CD79A/CD79B) that transmits activation signals upon HA binding (NIH, 2024). The interaction between HA and its specific BCR is the fundamental event in the induction of a protective humoral immune response, leading to the production of neutralizing antibodies that block viral entry into host cells (Wikipedia, 2024). Consequently, these BCRs are the central target of all influenza vaccines, which aim to stimulate the expansion of HA-specific B cells and the generation of long-lived memory B cells (Tesini et al., 2019). Understanding the repertoire and specificity of these receptors is crucial for overcoming challenges such as 'original antigenic sin,' where prior exposure to certain influenza strains biases the immune response, and for the development of universal vaccines that target conserved epitopes across diverse influenza subtypes (Wang et al., 2007).

Other names

Hemagglutinin-specific B-cell receptorHA-reactive BCRInfluenza-specific B-cell receptorAnti-HA B-cell receptor

The B-cell receptor (BCR) complex, consisting of a membrane-bound immunoglobulin and the CD79A/CD79B heterodimer, recognizes the influenza hemagglutinin (HA) protein. Binding of HA to the BCR triggers phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs), initiating downstream signaling (e.g., via Syk, PLC-gamma2) that leads to B-cell proliferation, affinity maturation, and differentiation into plasma cells and memory B cells (Tesini et al., 2019; NIH, 2024).