Mucosal-associated invariant T cells (MAITs) have potent antimicrobial activity and are abundant in humans (5%–10% in blood). Despite strong evolutionary conservation of the invariant TCR-α chain and restricting molecule MR1, this population is rare in laboratory mouse strains (≈0.1% in lymphoid organs), and lack of an appropriate mouse model has hampered the study of MAIT biology. Herein, we show that MAITs are 20 times more frequent in clean wild-derived inbred CAST/EiJ mice than in C57BL/6J mice. Increased MAIT frequency was linked to one CAST genetic trait that mapped to the TCR-α locus and led to higher usage of the distal Vα segments, including Vα19. We generated a MAIThi congenic strain that was then crossed to a transgenic
Yue Cui, Katarzyna Franciszkiewicz, Yvonne K. Mburu, Stanislas Mondot, Lionel Le Bourhis, Virginie Premel, Emmanuel Martin, Alexandra Kachaner, Livine Duban, Molly A. Ingersoll, Sylvie Rabot, Jean Jaubert, Jean-Pierre De Villartay, Claire Soudais, Olivier Lantz
The MAITCAST locus determines iVα19 levels in the thymus, is hematopoietic intrinsic, and leads to an increased usage of the distal Vα segments.