Evaluation of a monoclonal blocking enzyme-linked immunosorbent assay for the detection of Mycoplasma gallisepticum-specific antibodies.
A monoclonal blocking enzyme-linked immunosorbent assay (blocking-ELISA) was developed to detect antibodies to Mycoplasma gallisepticum (MG) in poultry sera with the help of a peroxidase-labeled monoclonal antibody (MAb) recognizing an epitope of a 56-kilodalton polypeptide (p56) of MG. Immunoglobulins from undiluted MG-positive sera prevent the MAb conjugate from attaching to its specific binding site on p56, which results in no color development. The opposite result--a strong color reaction--was obtained after incubation with MG-negative sera (or when no serum was added before the MAb conjugate). Results were expressed in percent inhibition or ELISA titers. The blocking-ELISA detected 84.7% positive chickens in an experimentally infected flock and 72.6% of chickens in naturally infected flocks, whereas the hemagglutination-inhibition (HI) test was positive only with 68.4% and 48.6% of these serum samples, respectively. All HI-positive serum samples reacted positively in blocking-ELISA. Of sera negative by the HI test, 51.6% and 46.8% proved to be positive when examined with the blocking-ELISA. Overall agreement between the ELISA and HI test was 76.8%. Infection with closely related M. synoviae did not induce any false-positive reactions in blocking-ELISA. There was a strong positive correlation between HI and blocking-ELISA titers (r = 0.83).
Czifra
G
G
Veterinary Medical Research Institute, Budapest, Hungary.
Sundquist
B
B
Tuboly
T
T
Stipkovits
L
L
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins / Q000276:immunology; D001667:Binding, Competitive; D002645:Chickens; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D000939:Epitopes; D005069:Evaluation Studies as Topic; D006385:Hemagglutination Inhibition Tests; D009174:Mycoplasma / Q000276:immunology*; D009175:Mycoplasma Infections / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D011201:Poultry Diseases / Q000175:diagnosis / Q000276:immunology*; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D000939:Epitopes