International Journal of Cell Cloning, Vol 2, 286-295, Copyright © 1984 by AlphaMed Press
Interference of a human leukocyte interferon preparation with stimulatory activities in leukocyte-conditioned medium for human hematopoietic stem cells
L Kanz, GW Lohr and AA Fauser
Medium conditioned by leukocytes in the presence of phytohemagglutinin
(PHA-LCM) promotes the growth of multilineage hemopoietic progenitors
derived from human bone marrow. However, PHA-LCM prepared in the presence
of a human leukocyte interferon preparation does not support mixed colony
formation. Crude PHA-LCM preparations were characterized by gel filtration,
affinity chromatography, and gel electrophoresis. The elution profile on
Sephacryl S-300 of PHA-LCM prepared without interferon showed a distinct
peak that stimulated the growth of pluripotent stem cells (CFU-gemm) and
committed precursors (CFU-c, BFU- e). Gel filtration of PHA-LCM, prepared
with 1000 U/ml of interferon, revealed a change in the elution profile. The
eluted material demonstrated no growth-promoting activities. We conclude
that the abolished stimulatory activity of PHA-LCM, prepared with human
leukocyte interferon, might be due to a reduced production of stimulatory
molecules, suggesting that interferon interferes with the molecular events
required for colony formation of committed and noncommitted hemopoietic
progenitors.
