Type 1 invariant natural killer T cell receptor (iNKT TCR) (iNKT TCR)

The Type 1 invariant natural killer T cell receptor (iNKT TCR) is a specialized heterodimeric antigen receptor expressed on the surface of invariant natural killer T (iNKT) cells, a unique lymphocyte subset that bridges innate and adaptive immunity (Bendelac et al., 2007, Annual Review of Immunology). Unlike conventional T cell receptors that recognize peptide antigens presented by MHC molecules, the iNKT TCR specifically recognizes lipid and glycolipid antigens presented by the non-polymorphic MHC class I-like molecule, CD1d (Borg et al., 2007, Nature). In humans, this receptor is defined by a highly conserved invariant alpha chain (Vα24-Jα18) paired with a restricted set of beta chains, most commonly Vβ11 (Crosby & Kronenberg, 2018, Nature Reviews Immunology). Upon engagement with potent agonists such as alpha-galactosylceramide (α-GalCer), the iNKT TCR triggers the rapid and massive secretion of cytokines like IFN-gamma and IL-4, which subsequently activate natural killer cells, dendritic cells, and conventional T cells. This potent immunomodulatory capacity makes the iNKT TCR a significant therapeutic target in oncology for orchestrating anti-tumor responses and in autoimmune diseases for restoring immune homeostasis (Dhawan et al., 2020, Frontiers in Immunology). Current drug development efforts, such as the synthetic agonist ABX196, aim to leverage this receptor to enhance the efficacy of cancer vaccines and other immunotherapies (NCT03897543).

Other names

Invariant NKT cell receptorVα24-Jα18/Vβ11 TCRSemi-invariant T cell receptorCD1d-restricted T cell receptorVα24-Jα18 T cell receptor

The iNKT TCR acts as an agonist-activated receptor that recognizes glycolipid antigens presented by the non-polymorphic CD1d molecule. Binding of an agonist like alpha-galactosylceramide (α-GalCer) to the TCR-CD1d complex triggers rapid intracellular signaling through the CD3 complex, leading to the immediate and robust secretion of both Th1 and Th2 cytokines (Bendelac et al., 2007, Annual Review of Immunology).