Establishment and phenotypic characterization of three new human myeloma cell lines (U-1957, U-1958, and U-1996).

Three new human myeloma cell lines (U-1957, U-1958, and U-1996) have been established in vitro. The cell lines are Epstein-Barr virus (EBV) negative, monoclonal, and aneuploid and should thus represent malignant cell populations and not EBV-carrying non-neoplastic B lymphoblastoid cell lines. The myeloma origin of the cell lines is also suggested by their capacity for production of monoclonal complete immunoglobulin (Ig) molecules (U-1957 and U-1958) or IgG light chains (U-1996) of the same type as the myeloma protein in vivo. All the cell lines have morphological features of plasmablasts-plasma cells but appear to represent slightly different stages of B cell differentiation. Thus, the U-1958 has plasma cell morphology, expresses only PCA-1 and OKT-10 but no other B cell antigens, and secretes 1.5 micrograms/mL of IgG/10(6) cells/24 hours. The U-1957 has plasma cell morphology and expresses Fc receptors and the LB-1 antigen in addition to the PCA-1 and OKT-10 antigens. This line produces only minimal amounts of IgG, which appears not to be secreted. The U-1996, finally, is a kappa light chain producer, has a plasmablast morphology, and expresses LB-1 in addition to the PCA-1 and OKT-10 antigens. All three cell lines are chromosomally heterogeneous and contain several markers with a 14q+ abnormality as a common characteristic abnormality. These new myeloma lines have been in continuous culture for approximately 3 years and are instrumental in studies of various aspects of the biology of human myeloma.