Comparison between Two In Vitro ELISA-Based Assays in the Determination of Antivenom Potency

The potency of therapeutic a ntivenom in n eutralizing the venom lethality has traditionally been evaluated in vivo using mice. For its obvious advantages, ELISA that measures the antibody levels has cautiously substituted t he in vi vo methods. In an at tempt to find out an in vitro alternative for t he in vi vo neutralizing potency, a comparative study between the activity and avidity, measured respectively via 4 conventional and N H SCN-elution ELISAs, of polyvalent antivenom wa s performed. The correlation coefficients between the neutralizing potency of a commercially available polyvalent anti-snake antivenom measured against seven medically i mportant Egyptian snake v enoms " Naja haje, N aja nigricollis, Walterinnesia ae gyptia, Cerastes cerastes, Cerastes vipera, Echis carinatus and Pseudocerastes fieldi" 4 were r = 0 .62 and r = 0 .83 for the activity and a vidity respectively. Thus, the NH SCN-elution ELISA, that measures the ant ivenom avidity would be more s uitable, though not absolute, alternative f or t he estimation of t he antivenom neutralizing potency.