Strain specific BAFF expression analysis in wild type (WT) mice and B-hBAFF mice by ELISA.Serum were collected from WT mice (+/+) and heterozygous B-hBAFF mice (H/+), and analyzed by ELISA with species-specific BAFF ELISA kit. Mouse BAFF was detectable in WT mice (+/+) and heterozygous B-hBAFF mice (H/+). Human BAFF was exclusively detectable in heterozygous B-hBAFF mice (H/+). ND: not detectable.