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Outer membrane protein A (OmpA) binds to and activates human macrophages
C Soulas1, T Baussant, J P Aubry
1Centre d'Immunologie Pierre Fabre, Saint-Julien en Genevois, France.
Journal of Immunology (Baltimore, Md. : 1950)
|August 18, 2000
Summary
Outer membrane protein A (OmpA) from Klebsiella pneumoniae binds to and activates macrophages. This interaction may initiate the host
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Outer membrane protein A (OmpA) is a conserved and abundant protein in Enterobacteriaceae.
- Understanding OmpA's interaction with host immune cells is crucial for deciphering bacterial pathogenesis and host defense mechanisms.
Purpose of the Study:
- To investigate the interaction between Outer membrane protein A (OmpA) from Klebsiella pneumoniae and macrophages.
- To determine if OmpA binding and internalization by macrophages trigger an immune response.
Main Methods:
- Utilized Alexa488-labeled recombinant OmpA (P40) from Klebsiella pneumoniae.
- Assessed P40 binding and internalization by murine and human macrophages using flow cytometry at different temperatures.
- Measured cytokine (IL-1β, IL-8, IL-10, IL-12, TNF-α) and nitric oxide (NO) production by macrophages.
Main Results:
- Alexa488-labeled P40 demonstrated dose-dependent binding and rapid internalization by macrophages.
- No binding or internalization was observed for the control protein, glycophorin A.
- P40 significantly upregulated the production of key inflammatory cytokines and nitric oxide in macrophages, and synergized with IFN-γ and LPS.
Conclusions:
- Outer membrane protein A (OmpA) from Klebsiella pneumoniae binds to and activates macrophages.
- Macrophage recognition of OmpA may represent an initial step in the host's antibacterial immune response.