Strain specific CCR1 expression analysis in homozygous B-hCCR1 mice by flow cytometry. Peritoneal exudative macrophages were collected from wild-type mice (+/+) and homozygous B-hCCR1 mice (H/H), and analyzed by flow cytometry with species-specific anti-CCR1 antibody. Mouse CCR1 was detectable in wild-type mice. Human CCR1 was exclusively detectable in homozygous B-hCCR1 but not in wild-type mice.