Establishment of Epstein-Barr virus-negative diffuse large cell lymphoma cell line with an 8;22 chromosomal translocation.

A new human B-cell lymphoma cell line was established from a pleural effusion of a patient with a diffuse large cell lymphoma which originated from an ileocecal tumor. The cell line, designated KAL-1, has been passaged 280 times over a period of 22 months. This cell line was successfully maintained in a chemically defined serum-free medium; its doubling time is approximately 24 h. Immunologically, the cells were demonstrated to express IgM lambda on the cell surface and to react with monoclonal antibodies to B-cell antigen including B1, B4, HLA-DR, and common acute lymphoblastic leukemic antigen but not with B2 and all the T-cell markers. Immunoglobulin gene analysis revealed rearrangements of both JH and C lambda. These data indicate that this cell line represents the B-cell lineage at the immature B-cell stage. This cell line was negative for Epstein-Barr virus nuclear antigen and had no detectable Epstein-Barr virus genome in cellular DNA. Chromosome analyses revealed that the cells carried an 8;22 chromosome translocation, reminiscent of variant type Burkitt's lymphoma. However, there was no histological evidence for Burkitt's lymphoma. Molecular studies showed that KAL-1 had deregulated high constitutive expression of c-myc. This cell line was demonstrated to be highly tumorigenic when injected into athymic nude mice. This tumor model should provide clues about the molecular mechanism involved in the pathogenesis of B-cell malignancy and appears to be a useful in vivo model for the study of molecular events during B-cell differentiation and therapeutic investigations.