Specificity of the 34-Kilodalton Immunodominant Protein of Mycobacterium avium subsp. paratuberculosis

• Published in: Clinical and diagnostic laboratory immunology Vol. 6; no. 1; pp. 146 - 148
• Main Author: Gilot, Philippe
• Format: Journal Article
• Language: English
• Published: American Society for Microbiology 01-01-1999; American Society for Microbiology (ASM)
• Subjects: Amino Acid Sequence; Animals; Antibodies, Bacterial; Antibody Specificity; Bacterial Proteins; Cross Reactions; Humans; Immunodominant Epitopes; Letters to the Editor; Life Sciences; Molecular Sequence Data; Molecular Weight; Mycobacterium avium paratuberculosis; Mycobacterium avium subsp. paratuberculosis; Mycobacterium bovis; Mycobacterium tuberculosis; Sequence Homology, Amino Acid; Species Specificity
• ISSN: 1071-412X; 1098-6588
• DOI: 10.1128/CDLI.6.1.146-148.1999

In their recent article, Coetsier and colleagues described the preparation of polyclonal and monoclonal antibodies directed against the 13.6-kDa carboxyl-terminal portion of the 34-kDa protein of Mycobacterium avium subsp. paratuberculosis. They used these immunoglobulins for specific histopathological diagnosis of Johne's disease (paratuberculosis). This 34-kDa protein was previously identified as an immunodominant antigen located at the surface of M. avium subsp. paratuberculosis. The protein was proved to contain both species-specific and cross-reacting B-cell epitopes, and it was suggested that proteins homologous to the 34-kDa antigen are present in M. bovis and in M. avium. The 13.6-kDa carboxyl end of the 34-kDa protein (peptide a362) was produced by genetic engineering. This part of the protein is immunodominant, hydrophilic, and exposed outside the bacteria, the hydrophobic amino-terminal moiety being presumably anchored in the cell envelope. By using on one hand sera of rabbits hyperimmunized against a362 (in incomplete Freund's adjuvant) and on the other hand sera of cows with tuberculosis or with paratuberculosis, it was observed that peptide a362 contains only B-cell epitopes specific to M. avium subsp. paratuberculosis and no epitopes common to 10 other tested mycobacterial species, including M. bovis BCG. This peptide was thus a good candidate for an enzyme-linked immunosorbent assay (ELISA) for paratuberculosis, and such a test was developed.