Surface marker characteristics an two established North American B

Tumor cell lines have been established in continuous culture from two North American Burkitt's lym- phomas. The SU-AmB-1 line, derived from a patient with low serum antibody titers to Epstein-Barr virus (EBV), was de- void of EBV genomes by the reaction for EBV-associated nu- clear antigen (EBNA), could not be induced to express EBV antigens, and was highly refractory to EBV superinfection. Conversely, the SU-AmB-2 cell line, derived from a patient with "African type" serology, yielded a positive EBNA reac- tion and was readily inducible and superinfectable. Although both cell lines possessed B (bone-marrow-derived) cell char- acteristics, they had different surface marker patterns. It is postulated that two different classes of undifferentiated B cell lymphomas exist, one of which is positive for the pres- ence of EBV genomes and occurs endemically in Africa and New Guinea and sporadically in other parts of the world, the other of which is EBV-negative and occurs sporadically throughout the world, including the endemic areas. Although Burkitt's lymphoma was first identified in North American patients by its striking resemblance to African cases (1, 2), a number of significant differences have emerged which justify a critical comparison of these malig- nancies at the cellular level. Whereas, both varieties have similar clinical presentations (3, 4), morphologies (5), and B (bone-marrow-derived) cell characteristics (6), cases of American Burkitt's lymphoma (AmBL), unlike those of Afri- can origin, are not endemic to certain regions (4), respond poorly to chemotherapy (7), often have lower serum anti- body titers to Epstein-Barr virus (EBV) (8, 9), and have not contained cellular EBV genomes detectable by nucleic acid