Cross-presentation of cutaneous melanoma antigen by migratory XCR1+CD103- and XCR1+CD103+ dendritic cells.

The question of which dendritic cells (DCs) cross-present peripheral tumor antigens remains unanswered. We assessed the ability of multiple skin-derived and lymphoid resident DCs to perform this function in a novel orthotopic murine melanoma model where tumor establishment and expansion is within the skin. Two migratory populations defined as CD103-XCR1+ and CD103+XCR1+ efficiently cross-presented melanoma-derived antigen, with the CD103-XCR1+ DCs surprisingly dominating this process. These results are critical for understanding how antitumor CD8+ T cell immunity is coordinated to tumor antigens present within the skin.