Recombinant clonal stable CHO cell line constitutively expressing full length human BCMA protein, also known as TNFRSF17, (Genbank #NM_001192). Surface expression of BCMA was confirmed by flow cytometry. Each stable clonal cell line was selected for different levels of BCMA expression, (H. M, L), to mimic different stages of cancer target cells with various BCMA expression levels.