Detection of an antigen (MY4) common to M. tuberculosis and M. leprae by 'tandem' immunoassay.
A novel 'tandem' immunoassay for the detection of mycobacterial antigen was devised using a monoclonal antibody (ML 34) both as solid phase 'capture' and as the 125I- or enzyme-labelled 'tracer' antibody. This antibody binds to the repeating epitopes (MY4b) of a water-soluble protease-resistant antigen from M. tuberculosis, M. leprae and some other species of mycobacteria. Optimal binding results could be obtained within 4 h by the consecutive incubation of ML34-coated microtitre plates with antigen followed by the labelled ML34 antibody. The binding of intact bacilli was positive for M. tuberculosis but not for M. leprae. These results suggested that the MY4 antigen is expressed on the surface of M. tuberculosis and internally within M. leprae. Analysis of subcellular fractions suggested that this antigen is a constituent of cell walls.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000032:analysis*; D007118:Immunoassay / Q000379:methods*; D051379:Mice; D009166:Mycobacterium leprae / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial