CHARACTERIZATION AND ENRICHMENT OF MACROPHAGE PROGENITOR CELLS FROM NORMAL AND 5-FLUOROURACIL TREATED MOUSE BONE-MARROW BY UNIT GRAVITY SEDIMENTATION

Abstract

Unit gravity sedimentation was used to characterize and enrich cells from normal, post-5-fluorouracil (FU) and post-5-fluorouracil plus endotoxin (FUEt) regenerating mouse bone marrow with respect to 2 classes of macrophage progenitor cells. The 2 classes of progenitor cells assayed were those responsive to the combined stimulus of pregnant mouse uterus extract (PMUE) plus human spleen conditioned medium (HUSPCM), and those responsive to PMUE alone. In contrast to the bimodal nucleated cell distribution of normal marrow, 7 day post-FU marrow exhibited a unimodal nucleated cell profile. In marrow from 7 day post-FUEt treated mice, in which marrow regeneration was accelerated, there was a reemergence of a 2nd nucleated cell peak. In addition, in 7 day post-FU and 7 day post-FUEt marrow there was a shift in the modal sedimentation velocities of both PMUE responsive and PMUE + HUSPCM responsive populations to higher values. The combined effect of these changes resulted in a marked increase in plating efficiencies of the peak enrichment fractions, reaching 12.5% in 7 day post-FUEt marrow. The highest yield of progenitor cells responsive to the combined stimulus of PMUE + HUSPCM compared to those responsive to PMUE alone were obtained in 7 day post-FU marrow.