Receptor-mediated binding and internalization of leukocyte elastase by alveolar macrophages in vitro.
Open Access
- 1 September 1979
- journal article
- research article
- Published by American Society for Clinical Investigation in Journal of Clinical Investigation
- Vol. 64 (3) , 824-833
- https://doi.org/10.1172/jci109530
Abstract
Radioiodinated leukocyte elastase was found to bind rapidly and specifically to alveolar macrophages in vitro. In contrast to the binding of pancreatic and bacterial proteases, leukocyte elastase binding did not require the presence of alpha 2 macroglobulin. The binding was inhibited by an excess of unlabeled enzyme and was saturable by increasing elastase concentrations. Leukocyte elastase binding thus met criteria for receptor-mediated binding, with and estimated association constant of 4.97 x 10(5) M-1 and an estimated total of 640 x 10(6) binding sites/cell. It differed from the previously described binding of lysosomal glycosidases to macrophages in that it was insensitive to trypsin pretreatment, did not require calcium ions, and was not inhibited by yeast mannan. High-resolution autoradiography indicated that the cell-associated radiolabeled leukocyte elastase was rapidly incorporated into phagolysosomes. Macrophage binding may have a role in clearance of leukocyte elastase from tissue sites where alpha 2 macroglobulin is absent or present in low concentration. Thus, enzyme uptake by alveolar macrophages may be an important factor in the amelioration of lung tissue injury by extracellular leukocyte elastase.This publication has 42 references indexed in Scilit:
- Elastase secretion by peritoneal exudative and alveolar macrophages.The Journal of Experimental Medicine, 1977
- Clearance of lysosomal hydrolases following intravenous infusionArchives of Biochemistry and Biophysics, 1976
- Clearance of lysosomal hydrolases following intravenous infusionArchives of Biochemistry and Biophysics, 1976
- The binding of human lactoferrin to mouse peritoneal cells.The Journal of Experimental Medicine, 1976
- Evidence for specific recognition sites mediating clearance of lysosomal enzymes in vivo.Proceedings of the National Academy of Sciences, 1976
- Human leukocyte granule elastase: rapid isolation and characterizationBiochemistry, 1976
- The existence of a second route for the transfer of certain glycoproteins from the circulation into the liverBiochemical and Biophysical Research Communications, 1976
- Inhibition of Elastase from Granulocytes by the Low Molecular Weight Bronchial Protease InhibitorScandinavian Journal of Clinical and Laboratory Investigation, 1976
- Uptake of proteinase-α-macroglobulin complexes by macrophages☆Biochimica et Biophysica Acta (BBA) - General Subjects, 1975
- HIGH-RESOLUTION AUTORADIOGRAPHYThe Journal of cell biology, 1962