Human BCA-1 (B Cell-Attracting chemokine 1), also known as BLC or CXCL13, is a recently identified new CXC chemokines. Human BCA-1 is a highly effective attractant for human blood B lymphocytes, but was inactive on freshly isolated or IL-2 stimulated T lymphocytes, monocytes and neutrophils. The human BCA-1 is a 10.1 kDa protein containing 85 amino acid residues