| abstract |
A homogeneous megakaryocyte colony stimulating factor (Meg-CSF) comprising a protein having an activity of forming a megakaryocyte colony from human or mouse myelloid cells in vitro and an activity of increasing the numbers of megakaryocyte precursor cells and megakaryocytes in vivo, said Meg-CSF being produced by culturing cell strains of a large human-derived pulmonary cell carcinoma, e.g. PC-13 strains, or human pulmonary carcinoma cell strains, i.e. MC-1 strains, separated as monoclonal cells from the PC-13 strains, recovering the supernatant of the resulting culture medium, separating the Meg-CSF from the supernatant, and purifying it by a newly developed purification technique. The obtained homogeneous Meg-CSF is a homogeneous protein having a molecular weight of about 23,000 according to gel filtration or about 20,000 according to SDS-PAGE and an isoelectric point of 4.5 to 5.5. The partial amino acid sequence of the protein has been determined. The homogeneous Meg-CSF is useful for treating a certain kind of thrombocytopenia. |