CELL-SURFACE SHEDDING BY FIBROBLASTS IN CULTURE

  • 1 January 1980
    • journal article
    • research article
    • Vol. 16  (7) , 519-529
Abstract
The metabolic fate of cell-surface components was studied by labeling the surface of cultured chick embryo cells with [14C]glucosamine for 24 h or by lactoperoxidase-catalyzed radioiodination. The cells were then cultured further in label-free medium for 24 h. At different time intervals thereafter, cells and culture medium were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The radioactivity profile of the metabolically labeled material in the medium was similar to that of the [125I]lactoperoxidase-labeled cells. The rate of disappearance of labeled macromolecular components from the cell surface was a mirror image of the rate of accumulation of these components in the medium. Analysis on 7-20% acrylamide gradient slab gel revealed that most of the labeled macromolecules in the medium comigrate with the surface micromolecules obtained from intact cells. At least some cell-surface components are shed in undegraded form. The possible biomedical implications of the detection of intact cellular membrane components in the circulation are discussed.