In vitro evidence for genetically determined variations in marrow erythroid cell sensitivity to chloramphenicol

The effect of chloramphenicol (CAP) was examined on the in vitro growth of CFU-E and CFU-C from four strains of mice: C57L/J, A/HEJ and their first generation hybrid LAF1, and the inbred strain C57BL/6J. The growth of marrow CFU-E from C57L/J and the hybrid LAF1 was inhibited by 82--96% at a CAP concentration of 10 microgram/ml compared to only 22--39% for CFU-E from A/HEJ and C57BL/6J. There was little difference in the degree of inhibition of CFU-C growth by CAP among the four strains, with that of C57L/J showing a slightly greater sensitivity to the drug. These results indicate a genetically-determined variation in the sensitivity of marrow erythroid cells to CAP.