A blocking ELISA using a monoclonal antibody for the serological detection of Mycoplasma hyopneumoniae

Abstract A blocking ELISA was developed by using a monoclonal antibody (4082-05-344-18) which specifically detected an epitope on the Mycoplasma hyppneumoniae 40 kDa membrane protein without cross-reacting with M flocculare or M hyorhinis . The results obtained with sera from specific pathogen-free pigs inoculated with M flocculare or M hyorhinis confirmed the specificity of the assay. An immunoblotting procedure was used to characterise the antibody response of pigs experimentally infected with M hyopneumoniae . Antibodies to the 40 kDa antigen were detected two weeks after infection and remained as major markers for at least 20 weeks. Cross-reacting antibodies to this antigen were not detected in convalescent sera from piglets infected with M flocculare or M hyorhinis . Sera from experimentally infected pigs were compared by means of the blocking ELISA and an indirect ELISA . The kinetics of ELISA antibodies after experimental inoculation were also studied. The detection of antibody was rather more stable for a longer time with the blocking ELISA than with the indirect ELISA . In an evaluation of more than 1000 sera from the field there was excellent agreement between the two methods.