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Some biological properties of outer membrane proteins of Shigella
D Witkowska1, A Czarny, M Mulczyk
1Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław.
Abstract:
Outer membrane proteins (OMP) derived from two antigenically different representatives of Shigella (Sh. flexneri 3a and Sh. sonnei phase I) were tested for the toxicity, pyrogenicity, ability to induce Shwartzman reaction as well as for their influence on the leukocyte system. LD50 dose determined on mice was 28 mg/kg for OMP of Sh. flexneri and 23 mg/kg for OMP of Sh. sonnei. Both preparations injected intravenously to rabbits caused moderate increase of body temperature, expressed by the value 1.8 degrees C. Intravenous administration of protein preparations to rabbits, induced at first leukopenia and then transient leukocytosis. When injected subcutaneously in the dose of 500 micrograms and after 24 h intravenously in the dose 100 micrograms, they produced slight hemorrhagic changes at the site of administration.
Insights
Outer membrane proteins (OMP) from Shigella flexneri and Shigella sonnei exhibit toxicity and pyrogenicity in animal models. These OMP influence leukocyte counts and can cause localized reactions upon administration.
Area of Science:
- Microbiology
- Immunology
- Toxicology
Background:
- Outer membrane proteins (OMP) are key components of Gram-negative bacteria like Shigella.
- Understanding the biological activities of OMP is crucial for vaccine development and understanding pathogenesis.
Purpose of the Study:
- To evaluate the toxicity, pyrogenicity, Shwartzman reaction induction, and effects on the leukocyte system of OMP from Shigella flexneri 3a and Shigella sonnei phase I.
Main Methods:
- Determined LD50 dose in mice.
- Assessed pyrogenicity by measuring body temperature increase in rabbits after intravenous injection.
- Monitored leukocyte count changes following intravenous administration.
- Evaluated Shwartzman reaction by subcutaneous and subsequent intravenous injections in rabbits.
Main Results:
- LD50 doses were 28 mg/kg for Sh. flexneri OMP and 23 mg/kg for Sh. sonnei OMP.
- Intravenous administration induced a moderate fever (1.8°C increase) in rabbits.
- Leukocyte response showed initial leukopenia followed by transient leukocytosis.
- Subcutaneous and intravenous injections resulted in slight local hemorrhagic changes.
Conclusions:
- OMP from both Shigella strains possess significant toxicity and pyrogenic properties.
- These OMP induce notable changes in the leukocyte system and local inflammatory responses.