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Relationship between the iron regulated outer membrane proteins and the outer membrane proteins of in vivo grown
K Choi-Kim1, S K Maheswaran, L J Felice
1Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, St. Paul 55108.
Abstract:
The SDS-PAGE patterns of the outer membrane protein (OMP) extracts of Pasteurella multocida strain P1059, grown under iron-restricted, iron-replete and in vivo conditions, were examined. The results showed that the iron-regulated outer membrane proteins (IROMPs) with molecular masses of 76 kDa, 84 kDa, and 94 kDa were expressed by bacteria grown in iron-restricted media. They were also expressed by in vivo grown P. multocida. Convalescent-phase sera, obtained from turkeys which had survived pasteurellosis, contained antibodies that reacted intensly with th three IROMPs. This indicated that these proteins were expressed in vivo. Bacteria expressing the IROMPs showed greater binding to Congo Red when compared to cells not expressing IROMPs. Cells expressing the IROMPs or its OMP extracts grown in iron-restricted media also showed greater binding to 59Fe-pasteurella siderophore (multocidin) when compared to bacteria or its extracts not expressing IROMPs. Convalescent-phase sera, which contained antibodies against the IROMPs, blocked this specific 59Fe-multocidin binding to IROMPs. Autoradiography was used to determine which of these IROMPs functioned as a receptor for the iron-multocidin complex. The results suggested that these three IROMPs have specific epitopes for binding to the iron multocidin complex.
Insights
Researchers identified three iron-regulated outer membrane proteins (IROMPs) in Pasteurella multocida that are crucial for iron uptake and potential targets for vaccines against pasteurellosis.
Area of Science:
- Microbiology
- Immunology
- Veterinary Science
Background:
- Pasteurella multocida causes significant diseases in animals, including pasteurellosis.
- Outer membrane proteins (OMPs) are key virulence factors and potential vaccine targets.
- Iron acquisition is essential for bacterial survival and pathogenesis.
Purpose of the Study:
- To identify and characterize iron-regulated outer membrane proteins (IROMPs) of Pasteurella multocida.
- To investigate the role of IROMPs in iron uptake and their potential as vaccine targets.
Main Methods:
- SDS-PAGE analysis of OMP extracts from P. multocida grown under different iron conditions (restricted, replete, in vivo).
- Immune reactivity assessment using convalescent-phase turkey sera.
- Congo Red and 59Fe-pasteurella siderophore (multocidin) binding assays.
- Autoradiography to identify specific receptor functions.
Main Results:
- Three IROMPs (76 kDa, 84 kDa, 94 kDa) were identified in iron-restricted and in vivo grown P. multocida.
- Convalescent-phase sera showed antibodies against these IROMPs, confirming in vivo expression.
- IROMPs enhanced bacterial binding to Congo Red and 59Fe-multocidin.
- Antibodies against IROMPs blocked 59Fe-multocidin binding, suggesting a receptor role.
Conclusions:
- The identified IROMPs are involved in iron acquisition by P. multocida.
- These IROMPs possess specific epitopes for binding the iron-multocidin complex.
- IROMPs are promising candidates for vaccine development against pasteurellosis.