Detection of chicken antibody to the protozoan parasite Eimeria tenella by antigen-coated microspheres

Abstract A sensitive immunoassay for detecting antibodies to the protozoan parasite of poultry Eimeria tenella , has been developed. Microspheres coated with parasite antigen are reacted with antibody-containing chicken serum followed by a fluorescent labeled second antibody and analyzed by flow cytometry. The assay was used to demonstrate that chickens, vaccinated with E. tenella sporozoite antigen, showed significant elevations in serum antibody levels after exposure to infection compared to non-vaccinates. The assay is reproducible and because antigen-coated microspheres are stable for up to 4 weeks at 4°C, a single batch can be used to analyze multiple serum samples.