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Human monocyte cell line (U937) releases suppressive IgG-binding factor(s)
European Journal of Immunology
|January 1, 1986
Summary
U937 cells release an IgG-binding factor (IgG-BF) that suppresses IgG synthesis. This factor specifically targets IgG production without affecting cell proliferation or other antibody types.
Area of Science:
- Immunology
- Cell Biology
Background:
- U937 cells express Fc gamma receptors.
- Investigating spontaneous release of suppressor material from U937 cells.
Purpose of the Study:
- Characterize the suppressor material released by U937 cells.
- Determine its specificity and mechanism of action on antibody synthesis.
Main Methods:
- Incubation of U937 cells in serum-free buffer.
- Affinity chromatography using Sepharose 4B-IgG immunosorbents.
- Assay of pokeweed mitogen-driven IgG synthesis.
- Gel filtration for molecular mass determination.
Main Results:
- U937 cells spontaneously release an IgG-binding factor (IgG-BF).
- IgG-BF specifically suppresses IgG synthesis, not IgM or IgA.
- Suppression is maximal at day 3 and does not affect cell proliferation.
- Two inhibitory peaks identified with molecular masses of 30-40 kDa and 60-73 kDa.
Conclusions:
- U937 cells produce a novel IgG-binding factor (IgG-BF) with immunosuppressive properties.
- IgG-BF exhibits specificity for IgG synthesis, suggesting a targeted immunomodulatory role.
- The identified molecular masses provide insights into the nature of IgG-BF.