Antivenom activity of rattlesnake blood plasma.

Abstract

MANY species of venomous snakes have a high resistance to their own venoms and to those from other individuals of the same species and other species1–4. The resistance is not absolute but it increases as the size of the snake increases, and varies also with the type of venom. Blood plasma or sera of several species neutralise the venom of the same species and of other species both in vivo and in vitro5–11. As Clark and Voris10 reported, the whole serum of the eastern diamondback rattlesnake (Crotalus adamanteus) neutralises lethal doses of C. adamanteus venom in mice and the protective capacity of the serum is associated with the serum albumin fraction. Mixtures of C. adamanteus serum and Venom show no evidence of precipitation, such as occurs when serum from animals hyperimmunised with C. adamanteus venom is mixed with C. adamanteus venom. The nature of the factor(s) in rattlesnake plasma, which neutralise rattlesnake venom toxins, and the mechanism of neutralisation are unknown. We have found that both western and eastern diamondback rattlesnake (C. atrox and C. adamanteus) blood plasma contain antivenom factor(s) and have a neutralisation capacity (NC), not only for C. atrox venom but also other rattlesnake venoms. The antivenom activity of C. atrox plasma is sufficiently potent, compared with commercial immunoglobulin antivenin, to be potentially useful in the management of snakebite.