Equine protozoal myeloencephalitis: antigen analysis of cultured Sarcocystis neurona merozoites.

This research article studied equine protozoal myeloencephalitis (EPM), specifically analyzing the antigens in the Sarcocystis neurona merozoites – a stage in the cycle of the parasite causing the disease. The results identified specific proteins that could be detected by a S. neurona antiserum and/or immune horse serum.

Objective of Research

• The main objective of this research was to study the antigens of Sarcocystis neurona merozoites through immunoblot analysis. Sarcocystis neurona is the primary cause of equine protozoal myeloencephalitis (EPM), a common neurologic disease in horses.

Materials and Methods

• The researchers used various antisera (blood serum with antibodies) produced in rabbits and horses for the antigen examination.
• They also used immune sera from seven cases of EPM and pre-suckle serum from a newborn foal.
• Immunoblot analysis was used to examine the antigens. In this process, the proteins are separated based on their size, transferred to a blotting membrane, and then probed with antibodies to detect the presence of specific proteins.
• The horse’s sera were measured using the indirect immunofluorescent antibody (IFA) method, a common technique to detect and measure antibodies in a sample.

Findings

• They were able to identify eight proteins that were only detected by S. neurona antiserum and/or immune serum sourced from EPM-infected horses.
• Through the IFA method, researchers discovered horses with or without EPM still had Anti-Sarcocystis IFA titers present. A titer is the concentration of an antibody, as determined by finding how far a sample can be diluted before it loses its ability to cause a reaction.
• The serum titers did not correspond to the specific bands recognized on the immunoblots. Meaning, there was no direct relationship between the concentration of antibodies in the sera and the specific protein bands on the immunoblots.

Implications

• The differentiated proteins may be characteristic of S. neurona merozoites—offspring cells produced through reproduction. This discovery may have implications for the accurate diagnosis of EPM and the development of potential therapeutic targets.