Development of an enzyme-linked immunosorbent assay (ELISA) for identification of venoms from snakes in the Agkistrodon genus.

An enzyme-linked immunosorbent assay (ELISA) using a purified myotoxin from the venom of Agkistrodon contortrix laticintus (broad-banded copperhead) as immunogen was developed for potential use in the identification of envenomation by snakes belonging to the genus Agkistrodon native to North America. The specificity of the assay was tested using a total of 43 venom samples from snakes of diverse geographic locations. Venom samples used for cross-reactivity determination represent eight snake families including 14 species from the genus Crotalus. The assay detected venom from all Agkistrodon species tested without significant cross-reactivity with other venoms except for samples from two species of Bothrops which do not occur naturally north of Southern Mexico. The detection limit of the assay was 2 ng/ml for homologous crude venom dissolved in normal human serum. The assay was highly accurate in correlating optical densities with venom concentrations (r = 0.997). The presence of the antigen in experimental envenomations was readily detected by the assay at an i.m. injection dosage of 0.1 microgram/g. This ELISA is a promising test for identification of envenomations by species of Agkistrodon found in most of North America. It can also be used to study the kinetics of the myotoxin in experimental envenomations.