B cell receptor and T cell receptor (BCR and TCR)

This entry improperly combines two distinct therapeutic targets: the B cell receptor (BCR) and the T cell receptor (TCR). Each is a unique molecule with distinct structure, function, and therapeutic relevance. They should ideally be treated as separate entries for accurate targeting, annotation, and downstream bioinformatic structuring[5][6]. The **B cell receptor (BCR)** and **T cell receptor (TCR)** are structurally related but functionally distinct antigen receptors critical for adaptive immunity. BCRs are membrane-bound immunoglobulins on B lymphocytes, comprising two identical heavy and two light chains, responsible for recognizing intact antigens and initiating B cell activation, antibody production, and antigen presentation[3][5][1][7]. TCRs, expressed on T lymphocytes, are heterodimers (usually alpha and beta chains) that specifically recognize peptide antigens presented by major histocompatibility complex (MHC) molecules on other cells, triggering T cell–mediated immune responses[1][6][7]. Both receptors initiate intracellular signaling upon antigen engagement, leading to cell activation, clonal expansion, and crucial immune functions. Structurally, BCRs and TCRs share a common dimeric architecture and signal via associated invariant accessory proteins, with evolutionary conservation in their transmembrane regions[2][5]. Despite these similarities, BCRs primarily mediate humoral immunity by facilitating antibody synthesis, while TCRs mediate cellular immunity through cytotoxic or helper functions[6][1][7]. Both are therapeutic targets in cancer, autoimmunity, and infection, but must be considered separately for scientific and clinical accuracy.

Other names

B cell antigen receptor (for BCR)B lymphocyte antigen receptor (for BCR)T cell antigen receptor (for TCR)T lymphocyte antigen receptor (for TCR)

Inhibition of BCR/TCR-associated kinases (BTK, SYK, Lck, Fyn, etc.); Depletion of B cells (anti-CD20 therapies, indirect impact on BCR); Blockade of downstream signaling, costimulation, or antigen presentation.