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The Role of Helicobacter pylori Proinflammatory Outer Membrane Protein and Propolis in Immunomodulation on U937
Hengameh Soudi1, Tahereh Falsafi1, Sara Gharavi2
1Microbiology Department, Faculty of Biological Sciences, Alzahra University, Tehran, Iran.
Background:
Regarding the important role of proinflammatory outer membrane protein (OipA) in the pathogenesis of Helicobacter pylori infection and immunomodulatory activity of propolis, we aimed to evaluate the immunogenicity effect of a purified recombinant OipA protein and propolis in the induction of two cytokines, interferon-gamma (IFN-γ) and interleukin-4 (IL-4), in a macrophage cell model.
Materials And Methods:
The recombinant protein used in the present study corresponding to the oipA expressing a 34-35 kDa protein. OipA protein was purified by Ni-NTA affinity chromatography. The purified OipA protein (2.5- 40 μg /mL) and the propolis ethanolic extract (5-40 μg/mL) were incubated with phorbol 12-myristate 13-acetate-treated human myelomonocytic cell line U937 cells. IL-4 and IFN-γ levels were measured after 48 hours of incubation using enzyme-linked immunosorbent assay.
Results:
The amounts of IL-4 and IFN-γ were significantly increased. The optimum concentration of OipA for the secretion of IL-4 was 5 μg/ml (P<0.0001). At higher concentrations, the amount of IL-4 diminished until suppression at 40 μg/mL. The optimum concentration of propolis, resulting in the most significant increased secretion of both IL-4 and IFN-γ was 40 μg/mL (P=0.0001 and P=0.0004).
Conclusion:
We found that an OipA concentration of 10 μg/mL was more effective for IFN-γ production; however, it was not effective for the high production of IL-4. Therefore, it is postulated that the OipA could mainly induce a Th1 response through the production of IFN-γ. We also observed propolis's capability to induce IFN-γ production; however, the effective concentration for this was the same as for IL-4. Therefore, as an adjuvant, proper concentration of propolis is required for OipA to give the optimum response.
Insights
This study shows that outer membrane protein A (OipA) from Helicobacter pylori primarily induces a Th1 immune response. Propolis can act as an adjuvant, but its concentration must be optimized for OipA to achieve the best immune response.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Helicobacter pylori infection involves the proinflammatory outer membrane protein A (OipA).
- Propolis possesses immunomodulatory properties.
- Understanding the immune response to OipA and propolis is crucial for therapeutic strategies.
Purpose of the Study:
- To evaluate the immunogenicity of purified recombinant OipA protein and propolis.
- To assess their effect on the induction of interferon-gamma (IFN-γ) and interleukin-4 (IL-4) cytokines.
- To investigate their roles in a macrophage cell model.
Main Methods:
- Recombinant OipA protein (34-35 kDa) was purified using Ni-NTA affinity chromatography.
- Human myelomonocytic U937 cells were treated with OipA (2.5-40 μg/mL) or propolis ethanolic extract (5-40 μg/mL).
- Interleukin-4 (IL-4) and interferon-gamma (IFN-γ) levels were quantified after 48 hours via ELISA.
Main Results:
- Both OipA and propolis significantly increased IL-4 and IFN-γ levels.
- Optimal OipA concentration for IL-4 secretion was 5 μg/mL, with suppression at 40 μg/mL.
- Optimal propolis concentration for both IL-4 and IFN-γ secretion was 40 μg/mL.
Conclusions:
- OipA (10 μg/mL) was more effective for IFN-γ production, suggesting a Th1 response induction.
- Propolis induced both IFN-γ and IL-4, but required specific concentrations for optimal effect.
- Propolis may serve as an adjuvant for OipA, necessitating careful concentration selection for optimal immune response.
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