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Coexistence of Helicobacter pylori spiral and coccoid forms in experimental mice
Abstract:
AIM:To infect mice with Helicobacter pylori and detect immune response against two form of H. pylori.METHODS:An isolate of H. pylori obtained from a patient with gastric cancer was used to infect mice. Fifty mice were divided into eight groups. Two groups served as negative control without any inoculation and internal negative control with 0.5M NaHCO(3) and brain heart infusion (HBI), respectively. Mice in each experimental group were first inoculated with 0.5M NaHCO(3) and then H. pylori suspension for 3 times at a 2-day interval. Mice from controls and infectious groups were sacrificed at a weekly interval postinfection. Gastric samples were trimmed, inoculated onto chocolate blood agar and then incujbated in microaerophilic atmosphere at 37° for 14 days. Sera were examined for immunoglobulins against H. pylori spiral and coccoid antigens by ELISA.RESULTS:After inoculation H. pylori was isolated in one mouse from one week postinfection.No H. pylori was detected in control mice. However,urease test was positive in 50% (5/10) control mice, 70% (7/10) mice inoculated with NaHCO(3) and BHI and 77% (23/30) mice infected with H. pylori. The systemic immune responses of the mice to H. pylori strain were determined by ELISA. The mice showed immune responses to both H. pylori spiral and coccoid antigens one week after infection with H. pylori. The peak mean absorbances of antibodies against spiral and coccoid forms were four weeks postinfection which showed 6 and 18 times higher than that of negative control group respectively (P < 0.01).CONCLUSION:Spiral and coccoid forms of H. pylori coexist in experimental mice studied.
Insights
Mice infected with Helicobacter pylori showed immune responses to both spiral and coccoid forms. These immune responses peaked at four weeks post-infection, indicating the coexistence of both H. pylori forms in mice.
Area of Science:
- Microbiology
- Immunology
- Gastroenterology
Background:
- Helicobacter pylori infection is a significant global health concern, often associated with gastric diseases.
- The bacterium exists in different morphological forms, including spiral and coccoid, which may influence the host immune response.
- Understanding the immune response to these distinct H. pylori forms is crucial for developing effective therapeutic strategies.
Purpose of the Study:
- To investigate the immune response in mice infected with Helicobacter pylori.
- To determine the host's immune reaction against both spiral and coccoid forms of H. pylori.
Main Methods:
- Mice were infected with an H. pylori isolate from a gastric cancer patient.
- Gastric samples were analyzed for H. pylori presence and urease activity.
- Serum immunoglobulin levels against H. pylori spiral and coccoid antigens were measured using ELISA.
Main Results:
- Helicobacter pylori was successfully isolated from infected mice.
- A significant increase in urease test positivity was observed in infected mice compared to controls.
- Mice developed systemic immune responses, with elevated antibody levels against both spiral and coccoid H. pylori forms by one week post-infection.
- Antibody levels peaked at four weeks, showing a 6-fold increase against spiral forms and an 18-fold increase against coccoid forms compared to controls (P < 0.01).
Conclusions:
- Both spiral and coccoid forms of Helicobacter pylori coexist and elicit immune responses in experimentally infected mice.
- The study demonstrates that the host immune system recognizes and responds to both morphological variants of H. pylori.