Biochemical characteristics of a human myeloid leukemia cell differentiation factor

A human lymphocyte-derived maturation-inducing activity, which mediates the differentiation of human myeloid leukemia cells HL-60 to monocytic cells, was purified and characterized. The maturation inducer is a single polypeptide with a molecular mass of 54,300 Daltons. A Pl range of 8.0-8.5 was determined along with the amino acid composition of the inducer. In cell cultures, the purified inducer mediated a growth reduction and a differentiation of leukemia cells to mature monocytes-macrophages, possessing complement receptors and phagocytic capacity.