Development of immunoassays for determination of circulating venom antigens during envenomations by coral snakes (Micrurus species).

A reverse agglutination assay and two capture enzyme-linked immunoassays (ELISAs) for the quantitative determination of Micrurus nigrocinctus nigrocinctus venom antigens in fluids were developed using affinity-purified polyclonal antibodies and a cocktail of three monoclonal antibodies. The lower detection limit was 0.3 mg/ml for the reverse agglutination assay and 4 ng/ml for the capture ELISAs. The optical densities of both ELISAs correlated very well with venom concentrations in the range 4-333 ng/ml (r = 0.99). The ability of these assays to detect venoms of several medically important Micrurus species was studied. Besides detecting homologous venom, both ELISAs were also useful to quantitate venom from M. fulvius, M. dumerilii carinicauda and M. alleni. Using biotinylated polyclonal antibodies, M. n. nigrocinctus venom antigens were detected in sera or plasma from rabbits and mice during experimental envenomations with lethal and sublethal venom doses. The assays described in this work are promising tests to estimate the severity of poisoning in envenomations by the most important coral snakes of North and Central America.