Immunological cross-reactivity of venoms from some Egyptian snakes and scorpions

The immunological cross-reactivity among the Elapidae, Viperidae and Buthdae venoms was detected in dot blot and western blot assays and quantified in ELISA as percentage of absorbance of heterologous versus homologous reaction. Mutual cross-reactivity between the Elapidae and Viperidae venoms was recognized, reflecting high inter-family relationship whereas only weak cross-reactions were observed between the scorpion and snake venoms. The anti-scorpion antivenom exceptionally binds a 30-35 kDa Cerastes cerastes venom component, revealing common antigenic components between scorpions and C. cerastes venom. Many of the moderate and weak cross reactivity in ELISA got unnoticed in the dot blot technique. This work primarily describes the commonality among venoms from remote source animals which is potentially important in the designation of venom detection kits and also in exploring common allergens responsible for cross-sensitization of patients to heterologous bites or stings leading to immediate hypersensitivity reactions

Assessment of the phospholipase A2 patterns of some Egyptian snakes venoms

Despite of the fact that functionally diverse phospholipase A2 variants of snake venoms are well characterized at the level of protein and gene sequences; the patterns of individual snake venom PLA2s are poorly known. We investigated the activity, molecular weights and isoelectric points of the phospholipase A2s of some medically important snake venoms in Egypt. Portrayal of the phospholipase A2 activity of the vipers, "Pseudocerastes persicus fieldi, Cerastes cerastes and Echis carinatus" and the elapids "Naja haje, Walterinnesia aegyptia and Naja nigricollis" venoms revealed that: 1- The elapid venoms, with the exception of Naja haje, displayed higher PLA2 activity than viper venoms; 2- The molecular weights of the phospholipase A2 variants were close to 14 kDa; 3- The major phospholipase A2s of Naja nigricollis were basic proteins while those of Walterinnesia aegyptia venom were acidic proteins; 4- The Naja nigricollis and Pseudocerastes persicus fieldi venoms possessed the highest phospholipase A2 activity while the Walterinnesia aegyptia and Pseudocerastes persicu fieldi had the highest hemolytic activity of the tested elapids and vipers, respectively; 5- The in vitro hemolytic activities of the venoms were inhibited by the heterologous antivenoms, suggesting that the venom hemolytic factor [s] have shared epitopes. The data provided biochemical information of snake venoms phospholipase A2 which allowed designing procedure for isolation of the phospholipase A2s to study their pharmacological effects