Identification of immuno-dominant antigens of Trypanosoma evansi for detection of chronic trypanosomosis using experimentally infected equines.

The researchers identified and isolated dominant, infection-specific antigens in Trypanosoma evansi, a parasite responsible for disease in livestock. This work may lead to better ways of detecting chronic cases of the disease.

Background of the Research

• The parasite Trypanosoma evansi causes a disease called surra in livestock. This affliction is widespread in many countries and causes frequent outbreaks in India.
• The disease’s prevalence is often reported using standard parasitological detection methods (SPDM), but antibody ELISAs are being increasingly favored. These use antigens produced from whole-cell lysate (WCL).

Aims and Methods of the Research

• The researchers attempted to identify and purify dominant antigens that initiate an immune response, specific to T. evansi infections.
• They utilized equine (horse/donkey) serum from experimentally infected animals and examined this serum using immuno blot techniques.
• Three groups of proteins were found to be dominant in the immune response, their molecular weights were 62-66 kDa, 52-55 kDa, and 41-43 kDa.

Results of the Investigation

• The protein group with a size of 62-66 kDa was consistently reactive with serum from a donkey infected with T. evansi, even up to 280 days after infection. This indicated the protein group’s potential as a marker for chronic infection.
• This protein group was isolated in bulk in its natural form and compared with the standard whole-cell lysate antigen (WCL).
• The isolated protein group demonstrated 100% sensitivity in the detection of early and chronic T. evansi infections, in both ELISA and immune blot tests. It was also found to be reactive against hyperimmune serum raised against a 66 kDa antigen, indicating these proteins are common and dominant in T. evansi’s secreted proteins.

Implications of the Research

• The findings suggest that the isolated antigen could be successfully employed to improve T. evansi detection, particularly in cases of chronic infection.
• By providing a more reliable tool for diagnosing surra, the study could lead to more effective surveillance and control of this livestock disease.
• This work contributes to the broader understanding of the immuno-dominant proteins in T. evansi, potentially informing treatment and vaccine strategies.