Adaptive immune receptor (AIR) (AIR)

Adaptive immune receptors, which include the B-cell receptor (BCR) and the T-cell receptor (TCR), are the fundamental molecules used by the immune system to recognize specific antigens (StatPearls, 2023). The BCR is a membrane-bound immunoglobulin complex on B cells that recognizes native antigens, while the TCR is a heterodimeric protein on T cells that recognizes peptide fragments presented by major histocompatibility complex (MHC) molecules (Janeway's Immunobiology, 2001). These receptors are characterized by extreme diversity generated through V(D)J recombination, allowing the immune system to respond to a near-infinite variety of pathogens and mutated self-proteins in cancer (NIH, 2023). In clinical practice, these receptors are primary targets for immunotherapy; for instance, CD3-targeting bispecific antibodies like blinatumomab redirect T cells to kill tumor cells, and CD79B-targeted antibody-drug conjugates like polatuzumab vedotin are used to treat B-cell malignancies (FDA, 2023). Furthermore, the engineering of synthetic versions of these receptors, such as Chimeric Antigen Receptors (CARs), has revolutionized the treatment of hematologic cancers by providing T cells with new, non-MHC-restricted specificities (Nature Reviews Drug Discovery, 2020). Modulation of these receptors is also critical in managing autoimmune diseases, where drugs like teplizumab target the TCR complex to preserve beta-cell function in type 1 diabetes (PubMed, 2023).

Other names

B-cell receptorT-cell receptorBCRTCRAntigen receptorLymphocyte receptorSurface immunoglobulin complexT-cell receptor-CD3 complex

Drugs targeting adaptive immune receptors typically function by binding to invariant subunits of the receptor complex, such as the CD3 epsilon chain in TCRs or CD79B in BCRs, to either deplete specific cell populations, inhibit T-cell activation in autoimmunity, or redirect T-cell cytotoxicity toward tumor cells using bispecific formats (StatPearls, 2023; FDA, 2023).