• XCR1, also known as GPR5 or CCXCR1, is a 38 kD, G-protein coupled, seven transmembrane receptor, and the only member of the "C" chemokine receptor family.
• XCR1 mediates chemotaxis of XCL1 and XCL2 (lymphotactin-1 and -2), and defines a subset of CD8α+ conventional dendritic cells capable of antigen cross-presentation.

Gene targeting strategy for B-hXCR1 mice. The exon 2 of mouse Xcr1 gene that encodes the full-length protein was replaced by human XCR1 exon 2 in B-hXCR1 mice.

Strain specific XCR1 expression analysis in homozygous B-hXCR1 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hXCR1 mice (H/H) and analyzed by flow cytometry with anti-XCR1 antibody. mXCR1 was detectable in wild-type mice and homozygous B-hXCR1 mice, as the antibody is cross-recognize both human and mouse XCR1. hXCR1 was detectable in homozygous B-hXCR1 mice.

Strain specific analysis of XCR1 mRNA expression in wild-type C57BL/6 mice and B-hXCR1 mice by RT-PCR. Spleen RNA were isolated from wildtype C57BL/6 mice (+/+) and homozygous B-hXCR1 mice (H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human XCR1 primers. Mouse Xcr1 mRNA was detectable only in wild-type C57BL/6 mice. Human XCR1 mRNA was detectable only in homozygous B-hXCR1 mice but not in wild-type mice.