Single K562 human leukemia cells express and are inducible for both erythroid and megakaryocytic antigens

In a previous study we explored the inducibility of erythroid, granulocytic, monocytic and megakaryocytic antigens in the human multipotent leukemia cell line K562. In this study we examine the relationship between induction into the two lineages for which inducibility is most marked: erythroid and megakaryocytic types. Specifically, does any cell manifest markers of both lineages? We show that 1) cultured without inducer, a minority of single cells expresses both erythroid and megakaryocytic antigens, i.e., glycophorin A and Plt-1 antigen, 2) thymidine-hypoxanthine and phorbol dibutyrate each induce each antigen, 3) the percentage of individual cells carrying both antigens increases under each of these inducing conditions, 4) the induction of each is not only relative in terms of percentage of total cells that are positive, but also absolute in terms of mean antigen per cell and (taking into account cell multiplication) total antigen per ml of culture, and 5) the inducibility of individual cells bearing both erythroid and megakaryocytic markers is confirmed by using a different inducer (butyric acid) and antibodies for different inducer (butyric acid) and antibodies for different erythroid and megakaryocytic antigens (VIE-G4 and AP-3, respectively).