Antigenic cross-reactivity between sixteen venoms from scorpions belonging to six genera

Abstract

Venoms of 15 scorpion species from Venezuela and one from Brazil were compared in their antigenic cross-reactivity with specific F(ab')₂ against Tityus discrepans (Td-antibodies), using the method of King and collaborators (). Our results show that Tityus venoms cross-reactivity (shared epitopes) with the venoms of other species within the genus tended to be less for a greater distance between the habitat of the species. A nonparametric linear regression of free Td-antibody binding to T. discrepans venom immobilized to a solid phase in the presence of other Tityus venoms versus distance showed binding = a + b × log₁₀ (distance) where: median (95% confidence interval) for a = 0.92 (7.43, 9.80) and b = 17.20 (4.15, 22.57) binding/log₁₀(Km); Spearman r_S = 0.783 with associated P = 0.006. Our results show that toxins from different Tityus species, targeting mammalian Na⁺ and K⁺ channels, are antigenically very similar. Venoms from species from other genera such as Centruroides, Broteas, Diplocentrus, Chactas, and Rhopalurus did not cross-react with Td-antibodies.

Keywords :

• Scorpion venom
• Antibodies
• Cross-reactivity
• Tityus