title: Interaction between alpha 1 antitrypsin and lymphocyte surface proteases: immunoregulatory effects.
abstract: Alpha 1 antitrypsin (alpha 1-AT) is the major plasma protease inhibitor. Radioiodinated alpha 1-AT binds to human lymphocytes. The binding is fast and reversible, and the cells can be saturated with a maximum of approximately 1.2 x 10(6) molecules of alpha 1-AT per lymphocyte. The receptor for alpha 1-AT is a surface-associated protease. Addition of alpha 1-AT completely inhibits cell surface proteolytic activity. Furthermore alpha 1-AT decreases 3H-thymidine incorporation into lymphocytes stimulated by B or T cell mitogens or by allogeneic cells. Since alpha 1-AT was shown to be produced by activated monocytes and to bind to lymphocytes, it is likely to represent a mediator of monocyte-lymphocyte interactions.
mesh_terms: D000818:Animals; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000201:enzymology* / Q000276:immunology; D051379:Mice; D010641:Phenotype; D011480:Protease Inhibitors; D013936:Thymidine / Q000378:metabolism; D000515:alpha 1-Antitrypsin / Q000494:pharmacology*
chemical_list: D011480:Protease Inhibitors; D000515:alpha 1-Antitrypsin; D004247:DNA; D013936:Thymidine