| Abstract: | Two unique cell lines, NALM-1 and BALM-2 derived from lymphoblast-like cells of chronic myelogenous leukemia and rare B cell acute lymphoblastic leukemia patients, respectively, were compared with fresh parent cells from the patients and with a Philadelphia chromosome positive K-562 cell line previously established from a chronic myelogenous leukemia patient in blastic phase. NALM-1 resembled the parent cells in the presence of Philadelphia chromosome, non-T/non-B acute lymphoblastic leukemia specific antigens and lack of T or B cell markers, whereas BALB-2, like the parent cells, had two chromosome markers and bore kappa, delta and mu immunoglobulins. NALM-1 lacked Epstein-Barr virus genome, whereas BALM-2 showed the presence of Epstein-Barr virus genome. K-562 cells lacked all the antigen markers examined. All cells had high DNA polymerase alpha activity and low DNA polymerase gamma activity. NALM-1, like the parent cells and unlike K-562 cells, had high terminal deoxynucleotidyl transferase activity of about 200 mu/mg DNA, whereas BALM-2, like its parent cells, had terminal deoxynucleotidyl transferase activity of 1-2 mu/mg DNA (1 u = 1 nmole Mn++-dGTP/h on dA12-18 initiator). Terminal deoxynucleotidyl transferase was characterized by its chromatographic and sedimentation behavior, thermal sensitivity and specific inhibition by streptolydigin and terminal deoxynucleotidyl transferase antisera. These results indicate that NALM-1 and K-562 may represent different phenotypes of cells in CML blastic crisis. Moreover, NALM-1 and BALM-2 seem to have retained the characteristics of original leukemic cells from which they may have been derived. |
