Adherent cell growth from murine bone marrow in liquid cultures. Inbred strain variability and effects of mutations affecting hemopoiesis.

The marrow cells of mice from seven hematologically normal strains (AKR/J, AKR/Cum, CBA/J, C3H/HeJ, C57B1/6J, DBA/2J, and RF/J) and of mice with five mutations in loci affecting hemopoiesis (W, Sl, nu, xid, NZB) were tested. The following parameters of adherent cell growth in 14 day liquid culture were analyzed: number and diameter of macroscopic adherent colonies, cellular composition with particular reference to the number of macrophage-like cells attached to a single fibroblast-like cell on peripheries of adherent colonies and the number of macrophage-like cells per eyefield of intercolony spaces. No qualitative differences were observed between tested genotypes in the cellular composition of adherent layers. These layers were uniformly made of colonies of fibroblast-like cells that were overgrown by macrophage-like cells. Macrophage-like cells grew also in intercolony spaces but this never occurred to fibroblast-like cells. At least using light microscopy and Wright's staining no morphological differences could be observed between either fibroblast-like cells or macrophage-like cells derived from marrow of various murine strains. This is of particular significance for Sl/Sld mice that suffer from the functional defect of hemopoietic microenvironment. On the other hand, large strain variability was observed in the number (5-16/10(6) marrow cells, 10.6 on the average) and diameter (1.9-3.7 mm, 2.9 mm on the average) of macroscopic adherent colonies. Among mutant genotypes, only NZB mice and animals with xid mutation formed significantly increased numbers of macroscopic colonies, while values for other mutant genotypes, Sl/Sld included, did not differ from normal littermate controls.