Exact definition of species-specific and cross-reactive epitopes of the 65-kilodalton protein of Mycobacterium leprae using synthetic peptides.

With the use of solid phase synthesis of peptides corresponding to major and minor peaks in a Hopp-Woods hydrophilicity plot, the epitopes for 10 of 14 known different mAb to the Mycobacterium leprae 65-kDa protein, a prominent T and B cell Ag of this bacillus, have been located in the primary structure. Five epitopes have been precisely mapped by using the synthetic peptides in inhibition ELISA experiments, and five others have been located on peptides of 22 amino acids or less in length. The epitope of an important species-specific antibody, IIIE9, which may be useful for seriodiagnosis of leprosy, appears to be distinguished from the epitope of the antibody IVD2, widely cross-reactive among mycobacteria, not by its sequence, but only by its critical residues. All epitopes studied appear continuous insofar as can be determined by this approach.