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A transforming growth factor beta-like immunosuppressive factor in immunoglobulin G-binding factor
C Bouchard1, A Galinha, E Tartour
1Laboratoire d'Immunologie Cellulaire et Clinique, INSERM U255, Institut Curie, Paris, France.
The Journal of Experimental Medicine
|December 1, 1995
Summary
Transforming growth factor-beta (TGF-beta) acts like immunoglobulin G-binding factors (IgG-BF) by suppressing antibody production. This suggests TGF-beta plays a role in regulating antibody responses through IgG-mediated feedback.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Immunoglobulin G-binding factors (IgG-BF) are immune system molecules that inhibit antibody production.
- The precise mechanisms and identity of factors involved in regulating antibody synthesis require further elucidation.
Purpose of the Study:
- To investigate the potential role of transforming growth factor-beta (TGF-beta) as an immunoglobulin G-binding factor (IgG-BF).
- To determine if TGF-beta suppresses antibody production similarly to known IgG-BFs.
Main Methods:
- In vitro suppression assays using mouse splenocytes and B cells stimulated with lipopolysaccharide or anti-IgM.
- Neutralization experiments with anti-TGF-beta antibodies.
- Gel exclusion chromatography to analyze IgG-BF activity.
- Binding assays using insolubilized IgG, F(ab')2, and bovine serum albumin.
Main Results:
- TGF-beta suppressed secondary in vitro antibody responses with kinetics similar to IgG-BF.
- The immunosuppressive activity of IgG-BF was neutralized by anti-TGF-beta antibodies.
- TGF-beta bound to IgG but not to F(ab')2 or bovine serum albumin, indicating IgG-binding capacity.
Conclusions:
- Data strongly suggest that TGF-beta functions as an IgG-binding factor (IgG-BF).
- TGF-beta likely plays a biological role in the negative feedback regulation of antibody responses mediated by IgG.