They have two modes of activation (1): MR1-dependent activation consists of TCR stimulation by MR1-presented antigens on infected cells to produce an inflammatory response toward bacterial/fungal infections, and (2) MR1-independent activation consists of the recognition of proinflammatory cytokines such as IL-12 and IL-15 secreted by infected cells to produce cytotoxic and inflammatory molecules against mainly viral infections [204]. Here, MR1 is linked to viral infectious disease.