Recognition of Lipid Antigens by CD1-restricted T cells (#137)
αβ and γδ-T cells represent distinct T cell lineages that express either αβ or γδ T cell receptors (TCRs) to recognise antigens. Natural Killer T (NKT) cells recognize lipid antigens presented by MHC class-I like molecule, CD1d. NKT cells are typically defined by the expression of a semi-invariant TCR (Vα24Vβ11) and by their ability to bind the lipid antigen α-Galactosylceramide (α-GalCer). We have previously shown that the NKT TCR adopts an evolutionarily conserved docking strategy to bind CD1d/α-GalCer to initiate a potent immune response. Here, we describe a novel population of α-GalCer reactive human T cells that expresses an unusual hybrid TCR comprising of a delta variable domain fused to an alpha constant domain, and paired with a Vβ chain. We termed these cells δ/αβ T cells and reveal that the δ/αβ TCR engages CD1d/α-GalCer in a completely different manner to the semi-invariant Vα24Vβ11 NKT TCR. While both δ/αβ T cells and Vα24Vβ11 NKT cells can bind CD1d/α-GalCer, these two subsets of cells show differential recognition of other lipid antigens. We also discuss the functional potential of δ/αβ T cells in comparison to conventional Vα24Vβ11 NKT cells. Collectively, this work expands the growing family of CD1/lipid reactive T cells and highlights how TCR diversity confers differential antigen reactivity.
- The molecular bases of δ/αβ T cell-mediated antigen recognition. Pellicci DG, Uldrich AP, Le Nours J, Ross F, Chabrol E, Eckle SB, de Boer R, Lim RT, McPherson K, Besra G, Howell AR, Moretta L, McCluskey J, Heemskerk MH, Gras S, Rossjohn J, Godfrey DI. J Exp Med. 2014 Dec 15;211(13):2599-615. doi: 10.1084/jem.20141764. Epub 2014 Dec 1.