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Recognition of immunologically important antigens in Bacteroides fragilis infection -an experimental study in mice
T Khanna1, D Panigrahi, N K Ganguly
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Abstract:
When the outer membrane proteins (OMP) of Bacteroides fragilis ATCC 23745 grown under seven different culture conditions were analysed by SDS-PAGE, five of the seven preparations showed similar protein profiles. When the three different OMP preparations were subsequently analysed by Western blotting, that from B. fragilis grown in brain heart infusion broth supplemented with haemin and menadione alone showed more immunodominant bands than those grown with additional cholesterol and methionine or cholesterol and cysteine. Only the former showed immunodominant proteins around 45.6 kDa and 66.2 kDa throughout the course of infection in mice. A protein corresponding to 97.4 kDa was found under all culture conditions. The results emphasise the importance of culture conditions in the expression of immunologically reactive antigens and also the possible use of such antigens in the serodiagnosis of B. fragilis infection.
Insights
Culture conditions significantly impact the expression of immunologically reactive outer membrane proteins (OMP) in Bacteroides fragilis. Specific OMP profiles under certain conditions may be valuable for serodiagnosing B. fragilis infections.
Area of Science:
- Microbiology
- Immunology
- Bacteriology
Background:
- Bacteroides fragilis is an opportunistic pathogen.
- Outer membrane proteins (OMP) are crucial for bacterial-host interactions and potential diagnostic targets.
- Understanding OMP expression under various conditions is key to identifying reliable antigens.
Purpose of the Study:
- To investigate the influence of different culture conditions on the expression of outer membrane proteins (OMP) in Bacteroides fragilis ATCC 23745.
- To identify specific OMP that are immunologically reactive and consistently expressed.
- To evaluate the potential of these OMP as diagnostic markers for B. fragilis infections.
Main Methods:
- Outer membrane proteins (OMP) from B. fragilis ATCC 23745 were analyzed using SDS-PAGE under seven different culture conditions.
- Western blotting was employed to analyze three distinct OMP preparations for immunodominant bands.
- In vivo studies in mice were conducted to assess protein expression during infection.
Main Results:
- Five out of seven culture conditions yielded similar OMP profiles via SDS-PAGE.
- B. fragilis grown in brain heart infusion broth with haemin and menadione showed more immunodominant bands compared to other conditions.
- Specific immunodominant proteins (45.6 kDa and 66.2 kDa) were observed in mice infected with bacteria cultured under specific conditions.
- A 97.4 kDa protein was consistently found across all tested culture conditions.
Conclusions:
- Culture conditions critically influence the expression of immunologically relevant antigens in B. fragilis.
- The identified immunodominant proteins, particularly those expressed under specific growth media, hold promise for the serodiagnosis of B. fragilis infections.
- Further research into these specific antigens could lead to improved diagnostic tools.
