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Published on: March 10, 2010
Immunoaffinity chromatographic isolation of a high molecular weight seroreactive protein from Mycobacterium leprae
R G Deshpande1, M B Khan, D A Bhat
1Department of Microbiology and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA.
Insights
Researchers isolated a key Mycobacterium leprae antigen, MLP, using immunoaffinity chromatography. This 22 kDa protein, identified as bacterioferritin, shows promise as an immunogen for leprosy diagnostics.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Leprosy is a chronic infectious disease caused by Mycobacterium leprae.
- Identifying specific M. leprae antigens is crucial for developing diagnostic tools and understanding disease mechanisms.
Purpose of the Study:
- To isolate and characterize Mycobacterium leprae antigens using immunoaffinity chromatography.
- To evaluate the potential of isolated antigens as diagnostic markers and immunogens.
Main Methods:
- Immunoaffinity chromatography utilizing immunoglobulins from leprosy patients and rabbit anti-M. leprae serum.
- Protein identification and characterization using molecular weight determination and N-terminal sequencing.
- Enzyme-Linked Immunosorbent Assay (ELISA) to assess reactivity with patient sera.
Main Results:
- A high molecular weight M. leprae protein (MLP) with a 22 kDa subunit was successfully isolated.
- The isolated MLP was identified as bacterioferritin, showing high homology with bacterial ferritin.
- ELISA demonstrated significant reactivity of MLP with sera from leprosy patients (100%) and tuberculosis patients (60%).
Conclusions:
- The isolated 22 kDa M. leprae protein (MLP) is bacterioferritin, a potential diagnostic marker.
- MLP's significant reactivity with patient sera highlights its importance as an immunogen in leprosy.
- Further research into bacterioferritin's role in M. leprae pathogenesis is warranted.
Abstract:
The purpose of this study was to isolate Mycobacterium leprae antigen(s) by immunoaffinity chromatography using immunoglobulins from leprosy patients and from rabbit anti-M. leprae hyperimmune serum coupled to CNBr-Sepharose 4B. A high molecular weight (M(r)) M. leprae protein (MLP) with a subunit M(r) of 22,000 was isolated. MLP was recognized by monoclonal antibody MMPII1G4 which is known to react with MMPII, a 22 kDa protein of M. leprae. The N-terminal sequence of the 22 kDa subunit (Met-gln-gly-asp-pro-asp-val-leu-arg-leu-leu-asn-glu-gln-leu-thr) was identical to MMPII and to antigen D (bacterioferritin) of M. paratuberculosis. It showed 44% homology with N-terminal end of E. coli bacterioferritin. In ELISA, MLP showed 100% and 60% positivity with leprosy and TB sera respectively as compared to normal healthy sera. The role of bacterioferritin in M. leprae and the importance of MLP as an immunogen has been discussed.
