Type I natural killer T cell receptor (iNKT cell receptor)

Type I natural killer T cell receptor (often abbreviated as iNKT cell receptor) is a semi-invariant T cell receptor expressed on type I NKT (invariant natural killer T) cells. These receptors comprise a highly conserved α-chain (Vα14-Jα18 in mice, Vα24-Jα18 in humans) paired with a limited set of β-chains (Vβ8.2, Vβ7, Vβ2 in mice; Vβ11 in humans)[4][6]. The iNKT receptor specifically recognizes glycolipid antigens, most notably alpha-galactosylceramide (α-GalCer), presented by the non-polymorphic, MHC class I-like molecule CD1d[2][4][6]. Upon activation, iNKT cells rapidly secrete a broad spectrum of cytokines (IFN-γ, IL-4, TNF-α, IL-2, granzyme B, perforin, etc.), influencing both the innate and adaptive immune systems[1][5]. They play critical roles in immune surveillance, tumor immunity, autoimmunity, infection, and inflammation by modulating the activity of dendritic cells, B cells, NK cells, and conventional T cells[2][6]. The iNKT cell receptor’s restricted specificity (for CD1d-lipid complexes) distinguishes this subset from conventional T cells[4]. Drugs such as α-GalCer and its analogs are being developed to exploit the immunomodulatory capacity of iNKT cells for cancer immunotherapy, infection control, and modulation of autoimmunity[2][6]. Therapeutic challenges include the risk of non-specific immune activation (cytokine storm), induction of immune anergy with repeated stimulation, and the wide variability in iNKT cell number and responsiveness between individuals[5][6]. The presence and function of iNKT cells, often tracked by their invariant TCR chain expression or cytokine responses, are considered a biomarker for both patient selection and treatment efficacy in immunotherapy trials.

Other names

invariant natural killer T cell receptoriNKT cell receptorinvariant NKT cell receptorVa14i NKT (mouse)Va24i NKT (human)classical NKT receptor

Agonist binding (e.g., glycolipid antigens like α-GalCer presented by CD1d) leading to rapid cytokine release (e.g., IFN-γ, IL-4), immune cell activation, and regulation; induction of cytotoxic activity against target cells