XCR1 and viral infectious disease: Notably, a chemokine receptor, XCR1, is specifically expressed in this DC subset in both, human and mice.19–22 Fusion proteins consisting of Ag proteins with an XCR1 ligand, XCL1, were generated and shown to be targeted to cDC1s or XCR1+ DCs, and induce efficient CD8+ T-cell or CTL responses against viral infection or cancers.23–25