Mycobacterium tuberculosis (Mtb) infects one-third of the world's population. Multidrug-resistant tuberculosis is present in virtually all countries, leading to an increased risk of failed antibiotic treatment. Development of novel TB vaccines is a global priority to fight tuberculosis. Although the licensed vaccine Bacillus Calmette-Guerin (BCG) has saved many children's lives, its protection against tuberculosis is insufficient. Previous vaccine development mainly focused on conventional T cells such as peptide-stimulated lymphocytes. We will target an unconventional T cell population, called mucosal-associated invariant T (MAIT) cells, which rapidly responds to other bacterial metabolites in early infection. We will determine mycobacterial metabolites for MAIT cell activation to facilitate the development of new TB vaccines.