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Inhibitor of peritoneal mononuclear phagocyte colony forming cells
Abstract:
We investigated an inhibitory factor present in mouse L-cell conditioned medium. This soluble factor, colony inhibitory factor (CIF), selectively inhibits the clonal growth of mouse peritoneal exudate (PE) macrophages in vitro. CIF appears to be a non-dialyzable macromolecule which was eluted by Sephadex G200 gel filtration at post-albumin fractions. It can be fractionated by ammonium sulfate precipitation within the range of 60%--70% saturated solution at room temperature. CIF is moderately heat labile and is destroyed by incubation at high pH. CIF is more effective on PE cells from C57 mice than on those from C3H or DBA mice. It also inhibits the clonal growth of committed stem cells for both granulocytes and macrophages present in bone marrow but to a much lesser degree. CIF is not interferon since no antiviral activity is demonstrable in the CIF preparation.
Insights
Researchers identified a colony inhibitory factor (CIF) in mouse L-cell conditioned medium that selectively inhibits macrophage growth. This macromolecule
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Mouse L-cell conditioned medium contains soluble factors influencing cell growth.
- Macrophage proliferation is a key process in immune responses and requires precise regulation.
Purpose of the Study:
- To investigate and characterize an inhibitory factor in mouse L-cell conditioned medium.
- To determine the effect of this factor on the clonal growth of macrophages.
Main Methods:
- Utilized Sephadex G200 gel filtration and ammonium sulfate precipitation for factor fractionation.
- Assessed inhibitory activity on mouse peritoneal exudate (PE) macrophages in vitro.
- Tested for antiviral activity to differentiate from interferon.
Main Results:
- Identified colony inhibitory factor (CIF), a non-dialyzable macromolecule, selectively inhibiting PE macrophage clonal growth.
- CIF fractionation occurred in post-albumin fractions and 60-70% ammonium sulfate saturation.
- The factor was moderately heat labile, pH sensitive, and showed strain-dependent efficacy (C57 > C3H/DBA).
Conclusions:
- Colony inhibitory factor (CIF) is a distinct soluble mediator regulating macrophage proliferation.
- CIF also affects hematopoietic stem cells but with lower potency.
- The factor is not interferon, indicating a specific role in myeloid cell regulation.