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Staphylococcus hyicus exfoliative toxin: purification and demonstration of antigenic diversity among toxins from
L O Andresen1, V Bille-Hansen, H C Wegener
1Danish Veterinary Laboratory, Copenhagen V, Denmark.
Abstract:
The exfoliative toxin produced by Staphylococcus hyicus strain 1289D-88 was purified as a single protein of approximately 30 kDa. Extracellular proteins of S. hyicus grown under small scale fermentation conditions were precipitated with ammonium sulfate. Separation of proteins was performed by hydrophobic interaction chromatography and successively anion exchange chromatography. The purified toxin was tested in a piglet skin assay. Weak epidermal lesions were macroscopically and microscopically similar to lesions caused by (NH4)2SO4-precipitated culture supernatant from the same strain. Addition of 0.5 mM CuSo4 to the purified toxin resulted in more intense skin alterations comparable to lesions caused by precipitated culture supernatant diluted 1:10. These results indicated that the activity of the exfoliative toxin was dependent on the presence of Cu2+. Polyclonal and monoclonal antibodies were prepared against the exfoliative toxin from strain 1289D-88. The in vivo activity of the exfoliative toxin could be neutralized by antibodies. It was shown that polyclonal as well as monoclonal antibodies only reacted with the toxin produced by two of nine well-defined virulent strains of S. hyicus. These results showed antigenic diversity among exfoliative toxins produced by different strains of S. hyicus.
Insights
The exfoliative toxin from Staphylococcus hyicus requires copper (Cu2+) for full activity, as demonstrated in piglet skin assays. Antibodies can neutralize this toxin, but antigenic diversity exists among different S. hyicus strains.
Area of Science:
- Veterinary Dermatology
- Microbiology
- Protein Biochemistry
Background:
- Staphylococcus hyicus causes exudative epidermitis in piglets.
- Exfoliative toxins (ETs) are key virulence factors, but their biochemical properties and strain variability are not fully understood.
Purpose of the Study:
- To purify and characterize the exfoliative toxin from S. hyicus strain 1289D-88.
- To investigate the role of copper ions in toxin activity.
- To assess the antigenic relationship between ETs from different S. hyicus strains.
Main Methods:
- Protein purification using ammonium sulfate precipitation, hydrophobic interaction chromatography, and anion exchange chromatography.
- In vivo piglet skin assay to evaluate toxin activity.
- Antibody production (polyclonal and monoclonal) and cross-reactivity testing.
Main Results:
- A single protein of approximately 30 kDa, identified as exfoliative toxin, was purified.
- Toxin activity was significantly enhanced by the addition of 0.5 mM copper sulfate (CuSO4), indicating Cu2+ dependence.
- Both polyclonal and monoclonal antibodies neutralized toxin activity in vivo.
- Antibodies only reacted with ETs from 2 out of 9 tested S. hyicus strains, revealing antigenic diversity.
Conclusions:
- The exfoliative toxin from S. hyicus strain 1289D-88 requires copper ions for maximal pathogenic activity.
- Antibodies can neutralize S. hyicus exfoliative toxin, offering potential for therapeutic or diagnostic applications.
- Significant antigenic variation exists among exfoliative toxins produced by different S. hyicus strains, impacting vaccine development and diagnostics.