Characterization of allergens in four South American snake species.

A 55-year-old herpetologist developed rhinitis, asthma, urticaria and anaphylaxis when handling 4 different viper snake venoms. Allergen characterizations were done using SDS-PAGE, IgE immunoblotting and IgE inhibition experiments. The most prominent immunoreactive proteins were analyzed by MALDI-TOF mass spectrometry, and peptide identity was demonstrated by homology with known peptide sequences. SDS-PAGE showed several protein bands ranging from 5 to 99 kDa in each of the 4 snake venoms. Immunoblotting demonstrated 4 IgE-binding bands in the Bothrops extract of about 60, 28, 14 and 7 kDa. The bands of 28 and 14 kDa were also present in Lachesis muta. Two IgE-binding proteins of about 50 and 35 kDa were found in Bothrops atrox and L. muta, respectively. A strong inhibition of IgE binding to immobilize Bothrops asper proteins was observed after preabsorption of sera with B. asper, B. atrox,Bothrops xanthograma and L. muta extracts. MALDI-TOF analysis showed a 14-kDa phospholipase and the 60- and 28-kDa proteins showed significant similarity with metalloproteinases. In this report we have characterized the snake venom allergens that can elicit IgE-mediated symptoms.