Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 29, 2003
Publication Date: N/A
Technical Abstract: Our laboratories have recently completed the genome sequence of the veterinary pathogen Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis), which causes Johne's disease in ruminant animals. Although the genomes of M. avium subsp. avium (M. avium) and M. paratuberculosis are highly similar at the nucleotide level, we have identified at least 21 predicted coding sequences present only in M. paratuberculosis. Nucleotide sequences representing each of these unique predicted coding regions were amplified and cloned into an E. coli expression vector encoding the maltose binding protein (MBP) affinity-purification tag. Ninety percent of expressed mycobacterial proteins were successfully purified under denaturing conditions. Purified recombinant M. paratuberculosis proteins were used in immunoblotting studies with sera from rabbits and mice immunized with whole cell preparations of M. paratuberculosis. These studies show that three of the 21 gene products are antigenic. Immunoblot analysis with sera from clinical and control cattle shows that these same M. paratuberculosis proteins are recognized in the context of infection. Collectively, these studies have used a genomic approach to identify novel M. paratuberculosis antigens that are not present in any other mycobacteria.