Maturation inducer activity and the process of human myeloid leukemia cell differentiation

The process and mechanism of human myeloid leukemia cell differentiation induced by T-cell lymphokine maturation inducer activity was investigated. The maturation inducer activity was purified from conditioned medium of normal peripheral blood lymphocytes and shown to be a 50,000 M.W. protein. The degree of maturation of myeloid cell cultures was directly related to the dosage of the inducer. The interaction of the leukemia cells with the inducer led to initiation of terminal differentiation to monocytic cells. Proliferation cessation of the leukemia cells and the expressions of mature monocytic cells indicated a continuous and multistaged process.