title: Soluble antigen induces T lymphocytes to secrete an endoglycosidase that degrades the heparan sulfate moiety of subendothelial extracellular matrix.
abstract: The antigen-mediated induction of heparanase, an endoglycosidase capable of degrading heparan sulfate from the subendothelial extracellular matrix (ECM), was investigated in a rat T lymphocyte cell line reactive against the basic protein (BP) of myelin. We found that nonactivated T lymphocytes could be induced to express heparanase activity following exposure to soluble but not to ECM-bound BP. The induction of heparanase was immunologically specific and independent of the presence of syngeneic or allogeneic antigen presenting cells (APC). However, anti-IA antibodies inhibited heparanase expression. Soluble BP induced secretion of heparanase into the culture medium within minutes, despite inhibition of protein synthesis. Cell lysates of T lymphocytes contained heparanase activity. Thus, T lymphocytes secrete a preformed heparanase following exposure to specific antigen.
mesh_terms: D000818:Animals; D000906:Antibodies; D002417:Cattle; D002460:Cell Line; D002478:Cells, Cultured; D003315:Cornea / Q000166:cytology; D003513:Cycloheximide / Q000494:pharmacology; D004727:Endothelium / Q000166:cytology* / Q000378:metabolism; D004790:Enzyme Induction; D005109:Extracellular Matrix / Q000378:metabolism* / Q000648:ultrastructure; D005966:Glucuronidase; D006025:Glycosaminoglycans / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000096:biosynthesis* / Q000378:metabolism; D006497:Heparan Sulfate / Q000378:metabolism*; D008297:Male; D004676:Myelin Basic Protein / Q000276:immunology*; D051381:Rats; D013601:T-Lymphocytes / Q000201:enzymology* / Q000276:immunology; D000099175:Heparanase
chemical_list: D000906:Antibodies; D003513:Cycloheximide; D005966:Glucuronidase; D006025:Glycosaminoglycans; D006026:Glycoside Hydrolases; D006497:Heparan Sulfate; D004676:Myelin Basic Protein; D000099175:Heparanase