Comparative transcriptomes reveal pro-survival and cytotoxic programs of mucosal-associated invariant T cells upon Bacillus Calmette–Guérin stimulation

To comprehensively characterize MAIT activation programs responding to different bacteria, we stimulated MAIT cells with E. coli to compare with Bacillus Calmette-Guérin (BCG), which remains the only licensed vaccine and a feasible tool for investigating anti-mycobacterial immunity in humans. Upon sequencing mRNA from the activated and inactivated CD8+ MAIT cells, results demonstrated the altered MAIT cell gene profiles by each bacterium with upregulated expression of activation markers, transcription factors, cytokines, and cytolytic mediators crucial in anti-mycobacterial responses. Overall design: Human blood mononuclear cells were magnetically sorted to enrich MAIT cells, which were stimulated with E. coli-, M. bovis, or Listeria-incubated MR1-expressing cells . After incubation, MAIT cells were further sorted into CD69+CD26++ and CD69-CD26+/- subsets from the Va7.2+CD161+CD4-CD8+ -gated population.