International Journal of Cell Cloning, Vol 2, 20-33, Copyright © 1984 by AlphaMed Press
The influence of fibroblast-like cells derived from canine fetal hematopoietic tissues on the regulation of lymphohematopoiesis
AK Klein, JA Lynch, JA Dyck, JA Shimizu, LA Fox and KA Stitzel
Media conditioned by fibroblast-like cells derived from organs active in
fetal lymphohematopoiesis were studied for their effects on adult
granulocyte/macrophage colony-forming units (CFU-GM). Fibroblasts from
fetal liver produced a factor stimulatory for CFU-GM, whereas fibroblasts
from fetal marrow produced a factor inhibitory for CFU-GM which was not
completely relieved by adding indomethacin to the assay. Our studies
indicated that neither fetal marrow nor fetal liver produced factors
affecting lymphocyte colony-forming units (CFU-L). Cell-cell interactions
between fibroblast-like cells derived from fetal liver or marrow and normal
adult CFU-GM were also studied. We observed that fibroblasts derived from
both fetal and adult marrow inhibited colony formation, whereas inhibition
in the presence of fetal liver fibroblasts was minimal. Loss of inhibitory
activity by a liver fibroblast cell line over repeated passages was seen.
Differential analysis of colonies formed above an adherent layer of fetal
marrow fibroblasts suggested that these fibroblasts suppress
myeloid/macrophage differentiation to a far greater degree than did adult
marrow fibroblasts. A role in the regulation of fetal lymphohematopoiesis
may be played by stromal fibroblasts.
