The Identification and Distribution of Cattle XCR1 and XCL1 among Peripheral Blood Cells: New Insights into the Design of Dendritic Cells Targeted Veterinary Vaccine

The chemokine (C motif) receptor 1 (XCR1) and its ligandXCL1 have been intensively studied in the mouse and human immune systems. Here, we determined the molecular characteristics of cattle XCR1 and XCL1 and their distribution among peripheral blood cells. Cattle XCR1 mRNA expression was mainly restricted to CD26+CADM1+CD205+MHCII+CD11b- cells in blood that were otherwise lineage marker negative (lin-); these represented a subset of classic dendritic cells (DCs), not plasmacytoid DCs. Some of these DCs expressed CD11a, CD44, CD80 and CD86, but they did not express CD4, CD8, CD163 or CD172a. Cattle XCL1 was expressed in quiescent NK cells and in activated CD8+ T cells. Cattle XCR1+ DCs migrated chemotactically in response to mouse, but not to human, XCL1. The distribution characters of cattle XCR1 and XCL1 suggested a vital role in regulation of acquired immune responses and indicated a potential for a DC targeted veterinary vaccine in cattle using XCL1 fused antigens.