Studies of arbin toxic action on tumor cells by immunoelectron microscopy
Journal
Journal of Ultrasructure Research
Journal Volume
73
Journal Issue
3
Pages
310-317
Date Issued
1980
Author(s)
Abstract
By using rabbit Fab-peroxidase conjugate against abrin, a toxic lectin, its mechanism of cell entry and localization in the cytoplasm of Ehrlich ascites tumor cells were studied by electron microscopy. The following sequence of events were noted: (a) binding of abrin to the cell surface; (b) cell membrane disintegration with or without endocytosis of abrin; (c) diffusion of abrin into cytosol either through disintegrated plasma membrane or through the disintegrated membrane of endocytotic vesicles; (d) binding of abrin to free and bound ribosomes. It is concluded that abrin not only can inhibit protein synthesis, but also may damage cell membranes directly. This conclusion is further substantiated by two additional experiments: (a) when the tumore cels were treated with 0.2% NaN3 at 4°C before incubation with abrin in order to suppress endocytotic activity, results of trypan blue cell viability tests indicated that the percentage of trypan blue-stained cells increased significantly as a result of abrin treatment; (b) when tumor cells were incubated with abrin-Sepharose particles at 4°C, about 40% of the tumor cells bound to the gel particles were stained with trypan blue. © 1980 Academic Press, Inc.
Type
journal article