Toxicity of two North American Loxosceles (brown recluse spiders) venoms and their neutralization by antivenoms

Abstract

The toxic, biochemical, and immunological characteristics of L. boneti and L. reclusa venoms and its neutralization by anti–L. boneti and anti–L. reclusa antivenoms were studied. The electrophoretic profile showed very similar patterns and the toxic activities were very close. Immunological studies showed cross-reactivity among L. boneti and L. reclusa venoms, with L. boneti and L. reclusa experimental antivenoms, and anti-L. gaucho and anti-L. laeta antivenoms. The venom of L. laeta showed low immunological reactivity with the North American Loxosceles antivenoms. Experimental anti-North American Loxosceles antivenoms protected mice of the systemic toxicity and were able to prevent necrosis in rabbit skin after the injection of the venom. Both antivenoms displayed cross neutralization. The results showed that both Loxosceles venoms have very close toxic, biochemical, and immunological characteristics, and that either monospecific antivenoms or an antivenom raised with L. boneti and L. reclusa venoms as immunogens could be useful for treating bites by North American Loxosceles spiders.

Keywords:

• Spiders
• Venom
• Loxosceles
• Antivenom
• Therapeutics
• Immunology
• Neutralization
• Toxicity

Acknowledgements

The authors greatly appreciate the collaboration of Dr. Norman I. Platnick from the American Museum of Natural History, New York for the identification of the North American Loxosceles spiders used in this work. The authors thank Dr. Alfonso Zavaleta-Martinez and Dr. Maria Salas-Arruz from the Peruvian University Cayetano Heredia for the provision of venom gland homogenates from Loxosceles laeta venomous apparatus. We greatly appreciate the collaboration of Blanca Ramos-Cerrillo in the purification of sphyngomyelinases from Loxosceles venoms and to Felipe Olvera for his collaboration in the laboratory work. We thank Dr. Carlos Sevcik from the IVIC, Caracas, Venezuela for helping us with the statistical interpretation of the results. We also thank Dr. Charlotte Ownby for allowing us the use of her laboratory for the extraction of L. reclusa venom.