A BLOCKING ELISA USING A MONOCLONAL-ANTIBODY FOR THE SEROLOGICAL DETECTION OF MYCOPLASMA-HYOPNEUMONIAE

A blocking ELISA was developed by using a monoclonal antibody (4082-05 -344-18) which specifically detected an epitope on the Mycoplasma hyop neumoniae 40 kDa membrane protein without cross-reacting with M floccu lare or M hyorhinis. The results obtained with sera from specific path ogen-free pigs inoculated with M flocculare or M hyorhinis confirmed t he specificity of the assay. An immunoblotting procedure was used to c haracterise the antibody response of pigs experimentally infected with M hyopneumoniae. Antibodies to the 40 kDa antigen were detected two w eeks after infection and remained as major markers for at least 20 wee ks. Cross-reacting antibodies to this antigen were not detected in con valescent sera from piglets infected with M flocculare ou 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 an tibody was rather more stable for a longer time with the blocking ELIS A than with the indirect ELISA. In an evaluation of more than 1000 ser a from the field there was excellent agreement between the two methods .