CONICET | Buscador de Institutos y Recursos Humanos

Introduction: Erucism (also called caterpillar dermatitis) is caused by envenomation by the larval stage of moths or butterflies (order Lepidoptera). There are multiple venomous species in Argentina, and they belong to the following families: Erebidae, Notodontidae, Limacodidae, Megalopygidae y Saturniidae. Objetives: The purpose of this work was to compare the protein composition and biological activities of bristle extracts of caterpillars belonging to the families Megalopygidae (Podalia sp.) and Saturniidae (Leucanella memusae Walker and Lonomia obliqua Walker). Methods: Alive caterpillars were collected from different localities of Misiones (Argentina), and transported and maintained in the Insectarium of the National Institute of Tropical Medicine (INMeT) (Argentina). Preparation of bristle extracts (venoms) was carried out as previously standardized for Brazilian L. obliqua bristle extracts. We performed one-dimensional SDS-PAGE aiming to know the protein profile, and Western Blotting (with the antivenom produced against the bristle extract from Brazilian L. obliqua in horses by Instituto Butantan, Brazil) to highlight the immunogenic protein components of the extracts. We also evaluated their abilities to hydrolyze molecules such as hyaluronic acid, azocasein, soybean lecithin and human fibrinogen. In addition, in order to understand its biological role in vivo, we tested the effect of these extracts upon coagulation on human plasma and aggregation of human platelets. Results: L. memusae and L. obliqua venoms exhibited a similar protein profile and also showed similar antigenic cross-reactivity with the Brazilian antivenom. Podalia sp. venom exhibits the highest hyaluronidase activity, with 10 µg of protein being able to degrade 80% of the hyaluronic acid used in the assay. Regarding the fosfolipase A2 activity, L. obliqua venom exhibits the highest level of degradation on soybean lecithin (43.3 U enz/mg). Although with different rate of hydrolysis, all three bristle extracts were able to degrade azocasein and human fibrinogen. Podalia sp. and L. obliqua venoms were able to shorten the clotting time triggered by calcium, while L. memusae venom inhibited the coagulation of plasma. L. obliqua extract directly induced aggregation in human washed platelets, and Podalia sp. venom impaired platelet aggregation induced by collagen. Conclusions: Altogether, these findings provide relevant information about the different physiopathological mechanisms through which these caterpillar bristle extracts can induce toxicity on human beings, and give insight into future directions for research on them.

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