An immunohistochemical investigation of the adult stage of the equine parasite Strongylus vulgaris.

The research focuses on studying the adult stage of the equine parasite Strongylus vulgaris using immunohistochemistry. This involves investigating which tissues in the worm react to antibodies, indicating that they either produce antigens or share common antigenic features.

Methodology

• The researchers collected samples of adult Strongylus vulgaris, a parasite found in horse’s caecum (part of the large intestine).
• The samples were embedded in a compound (paraplast) using standard methods and then sectioned for immunohistochemistry. Immunohistochemistry (IHC) is a method used to visually detect antigens in cells of a tissue section using selective antibodies linked to a visible marker.
• They raised antibodies in rabbits against the excretory-secretory product (ESP) and two specific proteins in it, with molecular weights of 28-30 kDa.

Experiments and Findings

• The team used several techniques including sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), enzyme-linked immunosorbent assay (ELISA), and immunoblotting to demonstrate the immunogenicity of the ESP and the two proteins (subunits).
• In the ELISA tests, both rabbit hyperimmune sera (serum having a high concentration of antibodies due to multiple stimulations) recognized the ESP and the two proteins consistently and strongly.
• The hyperimmune sera also recognized most ESP subunits of various molecular weights in immunoblots. This shows that these proteins have a strong antigenic (in other words, immune response triggering) presence.
• Using IHC and light microscopy, it was noted that specific tissues within the worm reacted strongly to the antisera, which will indicate that these tissues either produce antigens or contain structures that are similar to the antigens.
• Other tissues exhibited a weak reaction, which could be due to dispersion of antigen from adjacent/reactive tissues.
• Lastly, preimmune serum (serum obtained before the stimulation of the immune response) yielded a negative reaction with most worm tissues, which serves as a control in the experiment.

Conclusions

• The study concludes that certain tissues in the adult stage of the equine parasite Strongylus vulgaris either produce antigens or contain structures that share common features with the antigens. This finding provides insights that could potentially assist in developing targeted interventions or treatments against this parasite.