Immunochemical characterization of a protein associated with Mycobacterium leprae cell wall

Abstract

Nine monoclonal antibodies (MCA) to M. leprae were used to characterize a protein antigen of the bacillus. MCA IVD8 and IIIE9 were specific for M. leprae and reacted with an epitope (CWPa) present on a protein molecule associated with the cell wall fraction of M. leprae. This protein, designated cell wall-associated protein (CWP), lost its immunoreactivity upon treatment with trypsin and had an apparent MW of 65,000, though additional lower MW forms of the protein were observed by immunoblotting. Other cross-reactive epitopes (CWPb, CWPc, CWPd, and CWPe) were defined on the same molecule using 7 independent MCA. Therefore, M. leprae possesses a trypsin-sensitive, heat-stable protein associated with the cell wall which contains .gtoreq. 1 species-specific and 4 cross-reactive antigenic determinants.