Strain specific CSF1 expression analysis in B-NDG mice and homozygous B-NDG hCSF1 mice by ELISA. Spleens were collected from B-NDG mice and homozygous B-NDG hCSF1 mice stimulated with 100 μg/mL LPS in vivo for 2 hrs (200 μL/mouse). Grinding supernatant from the spleens was analyzed by ELISA. Mouse CSF1 was only detectable in B-NDG mice. Human CSF1 was exclusively detectable in homozygous B-NDG hCSF1 mice. Values are expressed as mean ± SEM.