Use of excretory/secretory antigens for the serodiagnosis of Anoplocephala perfoliata cestodosis.

This research article explores the use of whole worm extract (WWE) and excretory/secretory (E/S) antigens of Anoplocephala perfoliata for diagnosing equine cestodosis. It was found that E/S antigen provided better differentiation between horses with and without tapeworms. The E/S-ELISA test that was developed demonstrated a diagnostic sensitivity of 68% and specificity of 95%.

Characterisation of WWE and E/S antigens

• The researchers used SDS-PAGE, a method for separating proteins according to their electrophoretic mobility, to characterise whole worm extract (WWE) and excretory/secretory (E/S) antigens of Anoplocephala perfoliata, a type of tapeworm that affects horses. This provided them with detailed information about the individual proteins within these extracts.

Evaluation of WWE and E/S antigens for serodiagnosis

• With the characterised WWE and E/S antigens, the team used an enzyme-linked immunosorbent assay (ELISA), a plate-based assay technique designed for detecting and quantifying substances such as antibodies, to evaluate the effectiveness of these antigens in serodiagnosis of equine cestodosis, a disease caused by infestation of the horse’s intestine with tapeworms.
• During this evaluation, the researchers found that E/S antigen gave a better differentiation between sera (blood serum) samples from tapeworm-positive and tapeworm-negative horses compared to WWE.

Optimisation and Validation of E/S-ELISA

• After establishing that E/S antigen was more effective for serodiagnosis, they optimised and validated an E/S-ELISA method. This involved adjusting the parameters of the process and testing it against sera from horses with known tapeworm status to ensure its effectiveness.
• The optimised E/S-ELISA showed a diagnostic sensitivity of 68%, meaning it was able to correctly identify 68% of the tested samples that were truly tapeworm-positive. Meanwhile, the specificity in helminth-naive horses (horses that had no prior exposure to worms) was 95%, meaning it was able to accurately identify 95% of the samples that were truly tapeworm-negative.

Western Blot Analysis

• Finally, the researchers performed a western blot analysis – a widely used analytical technique used to detect specific proteins in a sample of tissue homogenate or extract – on tapeworm-positive and tapeworm-negative sera to identify the immunoreactive proteins of E/S antigen.
• The Western Blot result showed that the immunoreactive proteins of E/S antigen were those of 12 and 13 kilodaltons (kDa), a unit of molecular weight.