Antigenicity of recombinant maltose binding protein-Mycobacterium avium subsp. paratuberculosis fusion proteins with
Ratna B Gurung1, Douglas J Begg, Auriol C Purdie
1Faculty of Veterinary Science, University of Sydney, Camden, NSW, Australia.
Abstract:
Mycobacterium avium subsp. paratuberculosis causes Johne's disease (JD) in ruminants. Proteomic studies have shown that M. avium subsp. paratuberculosis expresses certain proteins when exposed to in vitro physiological stress conditions similar to the conditions experienced within a host during natural infection. Such proteins are hypothesized to be expressed in vivo, are recognized by the host immune system, and may be of potential use in the diagnosis of JD. In this study, 50 recombinant maltose binding protein (MBP)-M. avium subsp. paratuberculosis fusion proteins were evaluated using serum samples from sheep infected with M. avium subsp. paratuberculosis, and 29 (58%) were found to be antigenic. Among 50 fusion proteins, 10 were evaluated in MBP fusion and factor Xa-cleaved forms. A total of 31 proteins (62%) were found to be antigenic in either MBP fusion or factor Xa-cleaved forms. Antigenicity after cleavage and removal of the MBP tag was marginally enhanced.
Insights
Researchers identified antigenic proteins from Mycobacterium avium subsp. paratuberculosis, the cause of Johne's disease (JD) in ruminants. These proteins, expressed under stress, show potential for diagnosing JD in sheep.
Area of Science:
- Veterinary Microbiology
- Immunology
- Proteomics
Background:
- Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's disease (JD), a chronic infection in ruminants.
- MAP expresses proteins under stress conditions mimicking the host environment.
- These stress-induced proteins are potential targets for JD diagnostics.
Purpose of the Study:
- To identify antigenic proteins of MAP expressed during host infection.
- To evaluate the diagnostic potential of MAP proteins in sheep with JD.
Main Methods:
- Produced 50 recombinant maltose binding protein (MBP)-MAP fusion proteins.
- Screened fusion proteins using serum from JD-infected sheep.
- Evaluated antigenicity of 10 proteins after MBP tag cleavage.
Main Results:
- 29 out of 50 (58%) fusion proteins were antigenic.
- 31 out of 50 (62%) proteins showed antigenicity in either fusion or cleaved form.
- Antigenicity was marginally enhanced after MBP tag removal.
Conclusions:
- Several MAP proteins are recognized by the immune system of infected sheep.
- These antigenic proteins represent potential biomarkers for JD diagnosis.
- Cleavage of the MBP tag may improve diagnostic utility.
