Establishment and characterization of a new human Bence Jones-type myeloma cell line, NOP-2

A new human myeloma cell line NOP-2, producing immunoglobulin (Ig)-lambda-light chain was established from a patient with Bence Jones-type multiple myeloma. Morphologically, the cell line had plasmacytoid characteristics by light- and electron-microscopic examination. Phenotypic studies of NOP-2 cells revealed no surface Ig, but they were positive for cytoplasmic Ig-lambda, OKT10 (CD 38), and PCA-1. Epstein-Barr nuclear antigen was not detected. Chromosomal abnormalities of t(11;14) and t(8;22) were found in both NOP-2 cells and the original myeloma cells obtained from the patient. NOP-2 cells produced and secreted Ig-lambda light chain, but lacked immunoglobulins of any heavy chains. Rearrangements of both immunoglobulin heavy- and light-chain genes were observed in NOP-2 cells, though the cells expressed detectable mRNA only for Ig-lambda light chain. This cell line may serve as a useful model for understanding the hierarchy of human immunoglobulins and the pathophysiology of Bence Jones-type multiple myeloma.