Depressed immune surveillance against cancer: role of deficient T cell: extracellular matrix interactions.

Although T cells infiltrate malignant tumors, the local immune response is usually inefficient and tumors escape destruction. While extracellular matrix proteins strongly costimulate T cell responses in normal individuals, our studies indicate that peripheral blood T cells from cancer patients and tumor infiltrating cells respond poorly or are resistant to stimulative signals mediated by collagen I and IV and fibronectin. Moreover, the adhesive properties of cancer T cells are markedly depressed.

Disturbances of T-cell interactions with endothelium and the extracellular matrix proteins in a patient with Takayasu arteritis.

T-cell interactions with endothelium and the extracellular matrix proteins were studied in vitro in a patient with Takayasu arteritis. Markedly enhanced spontaneous adhesiveness to cultured endothelium and collagen IV and fibronectin were found to be paralleled by abolished responses to the costimulating action of collagens I and IV and fibronectin. Those abnormalities were partly corrected by immunosuppressive therapy.

Abnormalities in T cell interactions with the extracellular matrix proteins in a patient with Wegener's granulomatosis.

T cell interactions with the extracellular matrix proteins and cultured human endothelium were studied in a patient with Wegener's granulomatosis and other cases of vasculitis. Markedly enhanced costimulation of T-lymphoproliferative responses mediated by collagen and fibronectin were found in patients with severe forms of vasculitis, particularly with necrotizing changes. In addition, enhanced adhesion to collagen IV was found in the Wegener patient.

Human T cell adhesion to endothelium stimulated by membrane components extracted from strains of Bacteroides vulgatus (member of B. fragilis group).

Bacteroides fragilis is reported to be less virulent than other Gram negative rods, existing in normal gut flora (e.g. Enterobacteriaceae).