Antibody Responses to Natural Rattlesnake Envenomation and a Rattlesnake Toxoid Vaccine in Horses

Abstract

e Antivenom antibody titers following administration of rattlesnake venom for antivenom production in horses are well documented; however, antivenom antibody titers following natural rattlesnake envenomation in horses are not. Antibody titers produced in response to the commercially available rattlesnake venom vaccine are also not published. Our study objectives were to measure antivenom antibody titers in rattlesnake-bitten horses and compare them to titers in horses vaccinated with the rattlesnake venom vaccine. Additionally, titers were compared in pregnant versus nonpregnant horses to assess the affect of pregnancy on vaccine response and were measured pre-and postsuckle in foals of vaccinated mares to detect passive transfer of vaccine immunoglobulins. Blood samples were collected from16 rattlesnake-bitten horses. Thirty-six horses (11 pregnant mares, 12 nonpregnant mares, 13 geldings) were vaccinated using a Crotalus atrox venom toxoid vaccine. Blood was collected before administering each vaccination and 30 days following the third vaccination. Blood was collected from foals of vaccinated mares pre-and postsuckle. All serum was assayed for anti-Crotalus atrox venom antibodies using an enzyme-linked immunosorbent assay (ELISA). Rattlesnake-bitten horses had higher (P ‫؍‬ 0.001) titers than vaccinated horses. There was no significant difference between titers in vaccinated pregnant versus nonpregnant horses. One mare had a positive titer at foaling, and the foals had positive postsuckle titers. Antivenom antibody titer development was variable following natural envenomation and vaccination, and vaccine-induced titers were lower than natural envenomation titers. Further studies are required to determine if natural or vaccine antivenom antibody titers reduce the effects of envenomation.

Immunological Responses to Envenomation

“…However, a primary B cell response is slow (requiring days to weeks to become fully active), while defence against rapid venom action requires an immediate response (103). As an alternative to host antibodies, antivenom, produced in large mammals and purified for medical purposes, can provide passive immunity to victims of life-threatening envenomation (104)(105)(106).…”

Venom protection by broadly neutralizing antibody from a snakebite subject

“…Each snake produces 5-70 fractions, or unique proteins, in their venom, and there is abundant polymorphism of venom proteins even between individuals of a single snake species 12 . Thus, even if an antibody were discovered for every venom fraction of every venomous snake, it would not be possible to combine all of these antibodies into a single antivenom, as each antibody would be at far too low of a dose to be therapeutically relevant [13][14][15] .…”

Plasma proteome of buffaloes

“…The search for candidate molecules using the toxins and blood of large animals has reached its pinnacle in the last 20 years . In addition, biotechnological research involving farm animals has gained prominence in the pharmaceutical industry because these animals are more adequate experimental models than rodents and they can be used for the production of biopharmaceuticals . Ruminants, especially cattle, buffaloes, goats, and sheep, are responsible for the global production of 30% of the meat and 100% of the milk available for human consumption .…”