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T cell fibronectin: an unexpected inflammatory lymphokine.
1Department of Pathology, New York Medical College, Basic Science, Valhalla.
Lymphokine Research
|January 1, 1990
Summary
T cell fibronectin (FN), a lymphokine from activated T lymphocytes, potently attracts phagocytes to sites of immune response. This potent immune modulator enhances cellular influx and retention, crucial for delayed hypersensitivity reactions.
Area of Science:
- Immunology
- Cell Biology
Background:
- T cell fibronectin (FN) is produced by activated T lymphocytes.
- It functions as a lymphokine associated with delayed hypersensitivity reactions.
Purpose of the Study:
- To characterize the potent activities of T cell fibronectin.
- To elucidate the mechanisms underlying T cell fibronectin-mediated cellular responses.
- To investigate the role of T cell fibronectin in delayed hypersensitivity.
Main Methods:
- Assays measuring mononuclear phagocyte agglutination.
- Translocation assays using model extracellular matrices.
- Analysis of cellular metabolism and surface receptor interactions.
- Investigation of biophysical processes involving cell surface heparan sulfates.
Main Results:
- T cell fibronectin exhibits extreme potency (femtomalolar concentrations) in agglutinating mononuclear phagocytes and translocating monocytes and neutrophils.
- Macrophage agglutination requires cellular metabolism and specific cell surface receptor-FN domain interactions.
- Cellular translocation is a biophysical process mediated by heparan sulfate-FN domain interactions.
- T cell fibronectin does not affect peripheral blood lymphocytes.
Conclusions:
- T cell fibronectin is a highly potent lymphokine with dual functions in immune responses.
- Its ability to agglutinate phagocytes and facilitate cell translocation suggests a key role in initiating and sustaining delayed hypersensitivity.
- Secretion of T cell fibronectin may be critical for recruiting and retaining effector cells at inflammatory sites.