Differences in BFU-E growth in different mouse strains after stimulation with a mixed lymphocyte culture supernatant...

The growth of hemopoietic colonies in methylcellulose from bone marrow and spleen of CBA/Ca, DBA/2, BDF1, C57Bl/6, and NMRI mice was studied under stimulation by a mixed lymphocyte culture supernatant (MLC-BPA) which was necessary for the burst-forming unit E (BFU-E) growth in all strains. The number of pure and mixed BFU-E and non-BFU-E and their proportion varied between the strains; the BFU-E concentrations in the marrow were high in CBA/Ca and DBA/2 mice and low in C57B1/6. Furthermore, differences were seen in the requirement for serum and for erythropoietin. Optimal growth conditions were 4% fetal calf serum, 20% MLC-BPA, and 1 U erythropoietin/ml, but BFU-E growth was also obtained in the absence of serum. The differences in the BFU-E concentrations did not correlate with the numbers of colony-forming units S or the proportion of erythroblasts in the bone marrow smears.