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Receptor-mediated binding of Pasteurella multocida dermonecrotic toxin to canine osteosarcoma and monkey kidney
R K Pettit1, M R Ackermann, R B Rimler
1National Animal Disease Center, U.S. Department of Agriculture, Ames, Iowa.
Background:
Binding and internalization of Pasteurella multocida dermonecrotic toxin (PMDT) by toxin-sensitive canine osteosarcoma and monkey kidney (vero) cells was examined ultrastructurally.
Experimental Design:
Purified PMDT was conjugated to 20 nm colloidal gold particles in order to observe binding and internalization in the two cell lines at the ultrastructural level. The effects of various compounds on PMDT-vero binding were investigated to help elucidate the nature of putative vero cell receptors.
Results:
Colloidal gold-labeled PMDT was located at cell surfaces within 1 minute of its addition and rapidly transported to coated and noncoated invaginations of the plasma membrane. After extended incubation, gold particles were observed in endocytic vesicles, but not in any other intracellular structures. The magnitude of gold-PMDT cell association correlated with the cytotoxic sensitivity of the two cell lines. Early, but not late, addition of the lysosomotropic agent methylamine protected vero cells from the cytotoxic effects of PMDT without affecting binding. Biochemical and ultrastructural inhibition studies suggested the requirement for a ganglioside-type vero cell receptor.
Conclusions:
This is the first report describing binding and internalization of PMDT in host cells. Biochemical and ultrastructural results suggest that PMDT interacts with a ganglioside-type receptor on vero cells and is transported to the cytosol in endocytic vesicles which do not appear to fuse with lysosomes.
Insights
Pasteurella multocida dermonecrotic toxin (PMDT) binds and enters host cells via endocytic vesicles. This study suggests PMDT interacts with a ganglioside receptor on vero cells, crucial for understanding toxin internalization mechanisms.
Area of Science:
- Cell Biology
- Toxicology
- Microbiology
Background:
- Investigates the binding and internalization of Pasteurella multocida dermonecrotic toxin (PMDT) in canine osteosarcoma and monkey kidney (vero) cells.
- Examines the toxin's interaction with host cells at an ultrastructural level.
Purpose of the Study:
- To elucidate the mechanism of PMDT binding and internalization in susceptible cell lines.
- To identify the nature of the vero cell receptor for PMDT.
Main Methods:
- Utilized colloidal gold-labeled PMDT for ultrastructural observation of cell binding and internalization.
- Investigated the effects of various compounds on PMDT-vero cell interaction.
- Employed biochemical and ultrastructural inhibition studies.
Main Results:
- Gold-labeled PMDT rapidly bound to cell surfaces and was internalized via endocytic vesicles.
- Cell association with PMDT correlated with cytotoxic sensitivity.
- Early methylamine treatment protected cells from PMDT cytotoxicity without affecting binding.
Conclusions:
- This is the first report detailing PMDT binding and internalization in host cells.
- Results suggest PMDT interacts with a ganglioside-type receptor on vero cells.
- PMDT is transported to the cytosol in endocytic vesicles that do not fuse with lysosomes.