T cell fibronectin: an unexpected inflammatory lymphokine.
T cell fibronectin (FN) is a product of antigen and mitogen activated human, murine and guinea pig T lymphocytes. Operationally and functionally, T cell FN is a lymphokine associated with delayed hypersensitivity. T cell FN acts at femtomolar concentrations to agglutinate mononuclear phagocytes and translocate monocytes and neutrophils through model extracellular matrices, and is 1.1 x 10(4) to 2.3 x 10(6) times more potent than other FN for these activities. It does not act on peripheral blood lymphocytes. Macrophage agglutination mediated by T cell FN requires cellular metabolism and depends on interactions between multiple classes of cell surface protein receptors and FN gelatin- and cell-binding domains. In contrast, translocation of cells through artificial matrices mediated by T cell FN is a biophysical process dependent on interactions between surface heparan sulfates on responding cells and FN amino-terminal heparin-binding and gelatin-binding domains. The correlation between the ability of cloned murine T cell lines to produce FN and their ability to transfer delayed hypersensitivity reactions suggests that secretion of T cell FN may be an important element in the initiation of these responses. The double activity of T cell FN could allow it to enhance influx of phagocytic effector cells and retain monocytes at tissue sites of T cell activation.
Godfrey
H P
HP
Department of Pathology, New York Medical College, Basic Science, Valhalla.
D000818:Animals; D005109:Extracellular Matrix / Q000502:physiology; D005353:Fibronectins / Q000276:immunology / Q000502:physiology*; D006801:Humans; D006968:Hypersensitivity, Delayed; D007249:Inflammation / Q000503:physiopathology; D016023:Integrins / Q000502:physiology; D008222:Lymphokines / Q000502:physiology*; D015394:Molecular Structure; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology*
D005353:Fibronectins; D016023:Integrins; D008222:Lymphokines; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic; C035408:macrophage aggregation factor