MR1 and infection: To investigate which MHC class Ib molecules might present Mtb antigens to CD8+ T cells during infection, we enriched CD8+ T cells from Kb-/-Db-/-M3-/- mice and stimulated them with CFP-pulsed as well as Mtb-infected BMDCs derived from various mouse strains (i.e. B6, Kb-/-Db-/-M3-/-, Qa-1-/-, Qa-2null, MR1-/-, CD1d-/- and β2m-/- mice), and examined their cytokine production by ICS.