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Immunobiological activities of Helicobacter pylori porins
M A Tufano1, F Rossano, P Catalanotti
1Istituto di Microbiologia, Seconda Università di Napoli, Italy.
Abstract:
Studies were carried out on some biological activities of Helicobacter pylori porins in vitro. We extracted and purified a porin with an apparent molecular mass of 30 kDa. Human polymorphonuclear leukocytes preincubated with H. pylori porins showed a decrease of chemotaxis, of adherence to nylon wool, and of chemiluminescence. Used as chemotaxins in place of zymosan-activated serum or as chemotaxinogens in place of zymosan, the porins induced polymorphonuclear leukocyte migration. Human monocytes and lymphocytes cultivated in the presence of H. pylori porins released cytokines. Release of the various cytokines studied was obtained with differentiated kinetics and at various porin concentrations. Starting only 3 h after culture, tumor necrosis factor alpha is released quickly, reaching a peak at 18 h, at a porin concentration of 1 microgram/ml/10(6) cells. Interleukin-6 (IL-6) appears later, with a peak at 10 micrograms/ml/10(6) cells, while IL-8 is released after 6 h of culture, with a peak at 24 h, at a porin concentration of 10 micrograms/ml/10(6) cells, while IL-8 is released after 6 h of culture, with a peak at 24 h, at a porin concentration of 10 micrograms/ml/10(6) cells. Lymphocytes stimulated by H. pylori porins release gamma interferon after 18 h of culture at higher concentrations of porins (20 micrograms/ml/10(6) cells). Granulocyte macrophage colony-stimulating factor is released from 6 to 48 h at a concentration of 1 microgram/ml/10(6) cells, while both IL-3 and IL-4 are released after 18 h of culture at different porin concentrations (0.1 and 1 microgram/ml/10(6) cells, respectively). Our results lead us to think that during H. pylori infection, surface components, porins in particular, are able to induce a series of chain reactions ranging from the inflammatory to the immunological responses.
Insights
Helicobacter pylori porins modulate immune cell activity, influencing inflammatory and immunological responses during infection. These bacterial surface proteins trigger cytokine release and affect leukocyte migration and function.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Helicobacter pylori infection is a significant global health concern.
- Understanding the molecular mechanisms of H. pylori pathogenesis is crucial for developing effective treatments.
- Bacterial porins are outer membrane proteins involved in nutrient transport and host-pathogen interactions.
Purpose of the Study:
- To investigate the biological activities of Helicobacter pylori porins in vitro.
- To determine the effects of H. pylori porins on human immune cells, including polymorphonuclear leukocytes, monocytes, and lymphocytes.
- To analyze the cytokine release profiles induced by H. pylori porins.
Main Methods:
- Extraction and purification of H. pylori porin (30 kDa).
- In vitro assays using human polymorphonuclear leukocytes (PMNs) to assess chemotaxis, adherence, and chemiluminescence.
- Culturing human monocytes and lymphocytes with H. pylori porins to measure cytokine production (TNF-α, IL-6, IL-8, IFN-γ, GM-CSF, IL-3, IL-4).
Main Results:
- H. pylori porins inhibited PMN chemotaxis, adherence, and chemiluminescence but induced PMN migration when used as chemotaxins.
- Monocytes and lymphocytes released various cytokines, including TNF-α, IL-6, IL-8, IFN-γ, GM-CSF, IL-3, and IL-4, in a dose- and time-dependent manner.
- Specific cytokine release kinetics were observed, with TNF-α appearing early and others like IL-6 and IL-8 peaking later.
Conclusions:
- H. pylori porins play a significant role in modulating host immune responses during infection.
- These bacterial surface proteins can initiate inflammatory and immunological cascades by inducing cytokine release and affecting leukocyte function.
- Porins are key components of H. pylori that contribute to the complex host-pathogen interactions.