Abstract
Dendritic cells (DCs) have long been recognized as key regulators of immune responses. However, the process of their recruitment to peripheral tissues and turnover during homeostasis remains largely unknown. The chemokine CXCL14 (BRAK) is constitutively expressed in skin and other epithelial tissues. Recently, the human chemokine was proposed to play a role in the homeostatic recruitment of macrophage and/or DC precursors toward the periphery, such as skin. Although so far no physiological function could be demonstrated for the murine CXCL14, it shows a remarkable homology to the human chemokine. In order to elucidate the in vivo role of CXCL14, we generated a mouse defective for this chemokine. We studied various components of the immune system with emphasis on monocytes/macrophages and DC/Langerhans cell (LC) populations in different tissues during steady state but did not find a significant difference between knockout (CXCL14(-)(/)(-)) and control mice. Functionally, LCs were able to become activated, to migrate out of skin, and to elicit a delayed type of hypersensitivity reaction. Overall, our data indicate that murine CXCL14 is dispensable for the homeostatic recruitment of antigen-presenting cells toward the periphery and for LC functionality.