PRF1 and tuberculosis: Some studies indicate that Mtb-specific CD8 T cells may play an important role in protective immunity against TB via the production of perforin and/or cytolysin [76–80], while others indicate that the presence of Mtb-specific CD8 T cells may be detrimental [81], since Mtb-specific CD8 T cells were enriched in TB patients as compared to individuals with LTBI [53].