Characterization of a Factor Required for the Differentiation of Myeloid and Lymphoid Cells in Vitro

[摘要] The properties of a factor which is secreted by a cloned tumor cell line (JLS-V5) have been examined. The factor has been assayed in two culture systems. The factor induced the formation of colonies containing granulocytes and macrophages from mouse bone marrow cells cultured in a semi-solid agar medium. The factor also stimulated a normal primary immune response against erythrocyte antigens in immunologically unresponsive mouse spleen cultures. These spleen cultures were prepared from unimmunized mice in medium containing a deficient fetal bovine serum. The factor has been purified 500-fold from the serum-free culture supernatants of JLS-V5 cells. When the factor was treated with a variety of chemical and enzymatic reagents and then fractionated by gel filtration, the biologic activity for each culture assay resulted from the same molecular weight fractions. Acrylamide gel electrophoresis indicates the factor has a m.w. of 70,000 to 80,000.

[学科分类] 生物科学（综合）