A DEFINED MEGAKARYOCYTE PROGENITOR (CFU-MEG) ASSAY

ONE OF THE TOXIC EFFECTS OF ANTI-CANCER AND ANTI-HIV CHEMOTHERAPY IS THROMBOCYTOPENIA. THE COLONY FORMING UNIT-MEGAKARYOCYTE (CFU-MEG) IS A MEASURE OF THE NUMBER OF MARROW PROGENITOR CELLS CAPABLE OF PROLIFERATING AND DIFFERENTIATING INTO A MEGAKERYOCYTE COLONY. THIS ASSAY IS USEFUL IN EVALUATING THE CONTRIBUTION OF KNOWN (I.E., IL-6, STEEL FACTOR, IL-3) AND EXPERIMENTAL (I.E., MEG-CSF) CYTOKINES TO MEGAKARYOCYTE PRODUCTION. MEGAKARYOCYTES REMAIN IN THE MARROW AND RELEASE PLATELETS INTO THE BLOODSTREAM TO ASSIST IN CLOTTING. A DEFINED, SENSITIVE CFU-MEG ASSAY, CAN BE ADAPTED FOR USE IN: (1) MEASURING THE TOXICITY OF ANTI-HIV AND ANTI-CANCER DRUGS ON MEGAKERYOCYTE PRECURSORS, (2) DETERMINING THE CFU-MEG CAPACITY OF BONE MARROW HARVESTED FOR TRANSPLANT OR (3) IDENTIFYING THE PRESENCE OF MEGAKARYOCYTE COLONY- STIMULATING FACTOR (MEG-CSF) FOR PURIFICATION PURPOSES. THE PHASE I FEASIBILITY STUDY WILL RESULT IN THE DEVELOPMENT OF A MEGAKARYOCYTE PROGENITOR (CFU-MEG) ASSAY COMPOSED ONLY OF WELL- DEFINED COMPONENTS AND OPTIMIZED BY THE ADDITION OF RECOMBINANT CYTOKINES. BOTH EARLY ACTING CYTOKINES (I.E. STEEL FACTOR IL-11), TO INCREASE THE PROLIFERATION OF PROGENITOR CELLS, AND LATE ACTING CYTOKINES (I.E., IL-6), TO INCREASE DIFFERENTIATION OF MATURE MEGAKARYOCYTES, WILL BE ADDED IN COMBINATION.