B cell Attracting Chemokine-1 (BCA-1), also known as CXCL13, is expressed at high levels in lymphoid tissues such as the spleen, lymph nodes and Peyer's patches. It has been shown to activate signaling through the receptor BLR1 (Burkitt's lymphoma receptor 1) to chemoattract B cells. Recombinant BCA-1 is a non-glycosylated Protein, containing 87 amino acids, with a molecular weight of 10.3 kDa.