In this study, we defined the relative contribution of MHC Ia-, M3- and other MHC Ib-restricted CD8+ T cells in Mtb infection by comparing CD8+ T cell responses in B6, Kb-/-Db-/-, Kb-/-Db-/-M3-/- and β2m-/- mice upon aerosol infection with virulent Mtb. Here, B2M is linked to infection.