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The Antigenicity and Immunogenicity of Four Egyptian Snake Venoms.

1Wahby A. F., 1El-Hakim A. M. and 2Saad A. H.

1Department of Molecular Biology National Research Center, Cairo Egypt, 2Department of Zoology Faculty of Science Cairo University.

The immunological relationship and cross reactivity of the venoms from Naja haje, Pseudocerastes fieldi, Echis coloratus, Cerastes cerastes and the antisera raised against these venoms, were investigated using different assays. All the venoms contain highly antigenic and immunogenic proteins, which are quite different with respect to the number of bands and molecular weights. The immobilized venoms binds all the antivenom antibodies from the corresponding antisera and different proportions (20% to 76.7%) of antibodies from the heterologous antivenoms. Each of the venoms contained characteristic antigen(s), and others of shared identity with the non-homologous venoms. The antigenicity of venoms was greatly altered by reduction, indicating that both continuous and discontinuous epitopes were involved in the cross-reactions. The results demonstrated a high degree of immunological relationship among the venom components of the different species, and the presence of species specific antigens. The in vitro hemolytic activity of venoms was inhibited by the heterologous antivenoms, suggesting that the venom hemolytic factor(s) have shared epitopes. Also, a new mode for graphic representation of the neutralization data was used to compare the antigenicity of the hemolytic factor(s). The derived quantitative data revealed that the hemolytic factor(s) share most of their antigenicity. The data explored the importance of the non-shared factors as immunogens.