Strain specific analysis of CCL2 gene expression in wild-type mice and B-hCCL2 mice by RT-PCR. Mouse Ccl2 mRNA was detectable in stomach of wild-type mice (+/+). Human CCL2 mRNA was detectable only in homozygous B-hCCL2 mice (H/H) but not in wild-type C57BL/6 mice (+/+).

Strain specific CCL2 expression analysis in homozygous B-hCCL2 mice by ELISA. Serum was collected from wild-type mice (+/+) and homozygous B-hCCL2 mice (H/H) stimulated with anti-mCD3ε antibody for 4 hours in vivo, and analyzed by ELISA with species-specific CCL2 ELISA kit. Mouse CCL2 were only detectable in wild-type mice. Human CCL2 was exclusively detectable in homozygous B-hCCL2 mice but not in wild-type mice.