Immunological characterization of α antigen of Mycobacterium kansasii: B-cell epitope mapping

Mapping of B-cell epitopes on α antigen of Mycobacterium kansasii (K- α) was carried out by using recombinant truncated K-α fusion peptides. We observed that two immunodominant B-cell epitopes (amino acids 222-268 and 267-306) and one minor epitope (amino acid 249-286) were located in the C- terminal region of K-α. The other three minor B-cell epitopes were mapped in N-terminal (amino acids 80-98 and 99-166) and central (amino acid 174-204) regions of K-α. All defined epitopes were common to Mycobacterium tuberculosis and M. kansasii. Besides these common epitopes, a region in K- α (amino acid 290-319) revealed different reactivities between antibodies against K-α and α antigen of M. tuberculosis. These findings may provide a basis for development of serodiagnosis that can distinguish between M. kansasii and M. tuberculosis infections.