Immunization of equines with phospholipase A2 protects against the lethal effects of Crotalus durissus terrificus venom.

This study focuses on how immunizing horses and donkeys with a specific component of Crotalus durissus terrificus venom can increase their survival rates or even make them entirely resistant to the venom. Tests revealed this immunity correlated well with antibody levels detected by an ELISA method.

Experiment Overview

• The researchers conducted the study on four equines: two horses and two donkeys. Their objective was to determine whether immunization with Crotalus durissus terrificus venom or its nontoxic component, phospholipase A2, could enhance the survival rate of these animals when exposed to the venom.
• The experiment involved monitoring the animals over an extended period, spanning from the initial injection up to 270 days later, and also tracking their response 90 days after the last booster injection. The challenge involved administering a lethal dose of 200 mg of the crude venom.

Results and Findings

• The results indicated that the equines displayed increased survival time three days post-exposure or complete resistance to the venom.
• The researchers discovered that the resistance correlated well with antibody levels assessed using the ELISA (Enzyme-Linked Immunosorbent Assay) method. This method is a common laboratory technique used to detect the presence of specific antibodies in a blood sample. However, no such correlation was observed with the flocculation and neutralization assays. Flocculation measures the ability of antibodies to clump together, potentially neutralizing a toxic substance, while neutralization assays gauge an antibody’s ability to nullify the effects of a toxin.

Implications of the Study

• Phospholipase A2, a nontoxic component of the venom, may represent a safer substitute for the whole venom in creating commercial antisera. Antisera are blood sera containing antibodies against specific antigens and are used in the treatment of venomous bites and stings.
• The findings of the study also suggest potential for its use in prophylactic programs aimed at protecting animals, specifically equines, against venomous bites in regions where Crotalus durissus terrificus (a species of venomous snake) is prevalent.