Terminal deoxynucleotidyl transferase activity and cell surface antigens of two unique cell lines (nalm-1 and balm-2) of human leukemic origin

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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 BALM‐2, like the parent cells, had two chromosome markers and bore x, δ and μ 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 α activity and low DNA polymerase γ activity. NALM‐1, like the parent cells and unlike K‐562 cells, had high terminal deoxynucleotidyl transferase activity of about 200 μ/mg DNA, whereas BALM‐2, like its parent cells, had terminal deoxynucleotidyl transferase activity of 1‐2 μ/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.