Sequential expression of fucosyltransferase and N-acetylneuraminyltransferase activities in human leukemic cells arrested at different stages of maturation.

Fucosyl transferase (Fuc-T) and N-acetylneuraminyl-transferase (NeuAc-T) activities were determined in lysates of human neoplastic hematopoietic cells arrested at different stages of maturation. Leukemic non-T/non-B lymphoblasts and myeloblasts arrested at a very early stage of maturation displayed high Fuc-T and low NeuAc-T activities. T-lymphoblasts, further developed along the T-lymphocyte lineage, showed increased NeuAc-T activity. In contrast, lymphoid cells further developed along the B-lymphocyte lineage revealed low Fuc-T, and either low or high levels of NeuAc-T activity. These results suggest that during the process of cell maturation the expression of Fuc-T precedes that of NeuAc-T, and that in T-lymphocytes the expression of NeuAc-T is concomitant with the emergence of the T-cell receptor for sheep erythrocytes.