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Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages
Published on: February 22, 2017
The impact of ExHp-CD (outer membrane vesicles) released from Helicobacter pylori SS1 on macrophage RAW 264.7 cells
Abeer Ahmed Qaed Ahmed1, Fuyu Qi1, Ruizhu Zheng1
1Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China.
Abstract:
Bacterial-derived extracellular vesicles could play a major role in attenuating and treating diseases. They play a major anti-infection role by modulating immune responses against pathogens and preventing infection by inhibiting pathogen localization and proliferation. In this study, outer membrane vesicles (ExHp-CD) released by Helicobacter pylori SS1 (H. pylori) and total antigens isolated from H. pylori SS1 (AgHp) were evaluated for their immunogenic potential and their effect on macrophage RAW 264.7 cells. Results demonstrated that both ExHp-CD and AgHp induced T helper 2 (Th2) immune response, which was reported to be important in immune protection against H. pylori infections. Both ExHp-CD and AgHp produced high levels of IL-10 and IL-4, while no significant levels of IL-12 p70 or IFN-γ were detected. However, ExHp-CD showed a better effect on macrophage RAW 264.7 cells compared to AgHp. Macrophage RAW 264.7 cells stimulated with 5, and 10 μg/mL of ExHp-CD showed an increased ratio of CD206 (M2 phenotype marker) and a decreased ratio of CD86 (M1 phenotype marker). Moreover, results suggested that the immunogenic effect that ExHp-CD possesses was attributed to their cargo of Epimerase_2 domain-containing protein (Epi_2D), Probable malate:quinone oxidoreductase (Pro_mqo), and Probable cytosol aminopeptidase (Pro_ca). Results demonstrated that ExHp-CD possesses an immunological activity to induce Th2 immune response against H. pylori infection with results comparable to AgHp. However, ExHp-CD showed higher efficacy regarding safety, biocompatibility, lack of toxicity, and hemocompatibility. Thus, it could serve as an immunogenic candidate with more desired characteristics.
Insights
Bacterial outer membrane vesicles (ExHp-CD) from Helicobacter pylori induce a beneficial T helper 2 immune response, showing promise for treating infections. ExHp-CD demonstrated superior safety and biocompatibility compared to total antigens.
Area of Science:
- Immunology
- Microbiology
- Biotechnology
Background:
- Bacterial extracellular vesicles (EVs) are crucial for modulating immune responses and combating infections.
- Helicobacter pylori (H. pylori) infection is a significant global health concern.
- Understanding the immunogenic potential of H. pylori-derived EVs is vital for developing novel therapeutic strategies.
Purpose of the Study:
- To evaluate the immunogenic potential of outer membrane vesicles (ExHp-CD) from H. pylori SS1 and total antigens (AgHp).
- To assess the effects of ExHp-CD on macrophage RAW 264.7 cells.
- To identify the specific components within ExHp-CD responsible for its immunogenic activity.
Main Methods:
- Isolation and characterization of outer membrane vesicles (ExHp-CD) and total antigens (AgHp) from H. pylori SS1.
- Assessment of immune response by measuring cytokine production (IL-10, IL-4, IL-12 p70, IFN-γ).
- Evaluation of macrophage activation markers (CD206, CD86) following stimulation with ExHp-CD.
Main Results:
- Both ExHp-CD and AgHp induced a T helper 2 (Th2) immune response, characterized by high levels of IL-10 and IL-4.
- ExHp-CD demonstrated a more favorable effect on macrophage RAW 264.7 cells, promoting an M2 phenotype (CD206+) and reducing M1 markers (CD86+).
- The immunogenic properties of ExHp-CD were linked to its cargo proteins: Epimerase_2 domain-containing protein (Epi_2D), Probable malate:quinone oxidoreductase (Pro_mqo), and Probable cytosol aminopeptidase (Pro_ca).
Conclusions:
- ExHp-CD exhibits significant immunological activity, inducing a Th2 immune response against H. pylori infection, comparable to total antigens.
- ExHp-CD possesses superior safety, biocompatibility, and hemocompatibility profiles.
- ExHp-CD represents a promising immunogenic candidate for therapeutic applications against H. pylori infections.
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