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Published on: October 19, 2014
Purification and characterization of a human leukemia cell-derived immunosuppressive factor
1Department of Medicine, New York Medical College, Valhalla 10595.
Insights
Researchers purified a human leukemia cell-derived suppressor factor (LDSF) that inhibits normal lymphocyte proliferation and activation. This protein, isolated from HL-60 cells, is a stable 66 kDa molecule.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Leukemia cells can produce factors that suppress normal immune responses.
- Understanding these factors is crucial for developing targeted therapies.
Purpose of the Study:
- To purify and characterize a human leukemia cell-derived suppressor factor (LDSF).
- To investigate the effects of LDSF on normal human lymphocyte proliferation and activation.
Main Methods:
- Purification of LDSF from HL-60 cell culture supernatant using ion-exchange chromatography, gel filtration, and electrophoresis.
- Assessment of LDSF's effect on lymphocyte proliferation and activation in vitro.
- Determination of LDSF's molecular mass, stability, and effects on specific receptor expression.
Main Results:
- A protein factor (LDSF) suppressing lymphocyte proliferation and activation was isolated.
- Purified LDSF is a single-chain protein with a molecular mass of 66,000 daltons.
- LDSF is heat-stable and does not induce lymphocyte cytolysis or affect IL-2/transferrin receptor expression.
Conclusions:
- Leukemia cells constitutively produce a potent immunosuppressive factor.
- The purified LDSF represents a potential target for modulating immune responses in leukemia.
Abstract:
A human leukemia cell-derived suppressor factor (LDSF) capable of suppressing in vitro proliferation and activation of normal human lymphocytes was purified from human leukemic HL-60 cells. LDSF is constitutively produced by the cells and was purified from serum free culture supernatant by a combination of ion-exchange chromatography, gel filtration and electrophoresis. Purified LDSF was determined to be a single chain protein with an apparent molecular mass of 66,000 daltons. LDSF was not cytolytic to lymphocytes, was heat stable at 70 degrees C, and did not have any effect on IL-2 or transferrin receptor expression.
