BLC (B-lymphocyte chemoattractant) is a 12 kDa ELR-CXC chemokine. BLC showed high levels of expression in spleen, Peyer’s patches, and mesenteric lymph nodes. BLC is reported as the ligand of CXCR5. It attracts primarily B cells in vitro. Cell lines transfected with CXCR5 demonstrate both chemotaxis and calcium flux in response to BLC.