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Toxins not neutralized by brown snake antivenom.
Roopwant K Judge1, Peter J Henry, Peter Mirtschin
1Molecular Genetics and Evolution Group, Research School of Biological Sciences, Australian National University, Canberra 2601, ACT, Australia.
Toxicology and Applied Pharmacology
|November 1, 2005
Summary
Australian brown snake antivenom shows limited efficacy due to poor binding to low molecular weight venom proteins. This proteomic study reveals potential limitations in neutralizing venom activity, impacting treatment outcomes for snakebite victims.
Area of Science:
- Biochemistry
- Toxicology
- Proteomics
Background:
- Australian brown snakes (genus Pseudonaja) are responsible for most fatal snakebites.
- Current antivenom efficacy against these venoms is under scrutiny.
- Understanding venom composition and antivenom binding is crucial for effective treatment.
Purpose of the Study:
- To proteomically analyze the protein constituents of Pseudonaja snake venoms.
- To investigate the binding recognition of these venom proteins by the available antivenom.
- To assess the functional neutralization capacity of the antivenom against venom-induced physiological effects.
Main Methods:
- Two-dimensional gel electrophoresis (2-DE) for venom protein profiling.
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for protein identification.
- Immunoblotting to determine antivenom recognition.
- Rat tracheal organ bath assays to evaluate venom-induced contractions and antivenom neutralization.
Main Results:
- Pseudonaja venoms exhibited similar 2-DE profiles with major protein groups at 78-132 kDa, 32-45 kDa, and 6-15 kDa.
- Identified proteins included coagulant toxins and phospholipase A2 (PLA2) enzymes.
- Antivenom primarily recognized higher molecular weight venom components (>32 kDa), with minimal binding to lower molecular weight species (6-32 kDa).
- Antivenom failed to neutralize tracheal contractions induced by Pseudonaja affinis affinis, Pseudonaja nuchalis, and Pseudonaja textilis venoms, irrespective of PLA2 activity.
Conclusions:
- This is the first proteomic study of Pseudonaja venoms, revealing significant limitations in the current brown snake antivenom's binding to low molecular weight venom proteins.
- The antivenom's poor recognition of low molecular weight components may explain its ineffectiveness in neutralizing venom-induced physiological effects.
- Further research is needed to develop antivenoms with broader recognition profiles for improved treatment of Australian brown snake envenomation.