Characterization of monoclonal antibodies developed against Sarcocystis neurona.

The research article discusses the development of two different monoclonal antibodies for the diagnosis of equine protozoal myeloencephalitis (EPM) in horses, a prevalent neurological disease in North America. The study aims to improve EPM detection by utilizing these antibodies to identify Sarcocystis neurona, the protozoal parasite that causes the disease.

Understanding EPM and Sarcocystis neurona

• Equine protozoal myeloencephalitis (EPM) is a protozoal parasite infection in horses that affects the central nervous system. It is the most commonly diagnosed neurologic disease in North American horses.
• Sarcocystis neurona is the causative protozoal parasite of EPM. Approximately half of the horses in certain US regions test positive for this parasite. However, not all of these ‘seropositive’ horses show clinical signs of EPM.
• EPM is usually diagnosed through detailed clinical examination and cerebrospinal fluid antibody evaluation. After an affected horse’s death, the brain stem and spinal cord are analyzed to confirm the presence of EPM-compatible lesions. However, detecting the organisms directly is challenging with routine staining methods.

The Monoclonal Antibodies: mAb 2A7-18 and mAb 2G5-2

• This study developed two different monoclonal antibodies against the merozoite stage of Sarcocystis neurona. Monoclonal antibodies are antibodies that are made by identical immune cells, cloned from a single parent cell, which bind to the same part of an antigen.
• The two monoclonal antibodies, mAb 2A7-18 and mAb 2G5-2, were created with the S. neurona UCD-SN1 strain.
• The antibodies’ effectiveness was assessed using immunoblot, immunofluorescence, immuno-electron microscopy, and immunohistochemistry tests. These tests checked how well the antibodies could identify S. neurona.
• MAb 2G5-2 was successful in responding to different S. neurona isolates that were distinct antigenically. On the other hand, mAb 2A7-18 appeared to have limited capacity to recognize different isolates.
• These monoclonal antibodies recognize protein epitopes of two different immunodominant proteins of S. neurona. An epitope, or antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells.