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The location of surface antigens of Bordetella pertussis by immuno-electron microscopy
Abstract:
Immuno-electron microscopy using colloidal gold-tagged monoclonal antibodies (McAbs) has been used to detect antigens on the surface of Bordetella pertussis cells. McAbs to serotype-specific agglutinogens 2 and 3 labelled fimbriae in a serotype-specific manner. An attempt was made to determine whether individual fimbriae of serotype 1.2.3 cells bear both antigens 2 and 3. In double labelling experiments, individual cells were found to label with McAbs to antigen 2 (3 nm gold) and to antigen 3 (15 nm gold). Many fimbriae labelled with only one of these reagents, but there were instances where both labels could have been attached to the same fimbria. No fimbrial labelling was obtained with McAb to agglutinogen 1. Gold-tagged McAbs to filamentous haemagglutinin (FHA) labelled neither the fimbriae nor the surface of B. pertussis cells. Unfixed cells on electron microscope grids appeared to shed FHA readily. After fixation, a small proportion of cells bore aggregates of FHA which labelled specifically with anti-FHA McAb-gold. Results with one McAb to lymphocytosis promoting factor indicated that this antigen may be more intimately associated with the surface of B. pertussis than is FHA.
Insights
Monoclonal antibodies detected specific antigens on Bordetella pertussis fimbriae. Some fimbriae may possess both antigen 2 and 3, while filamentous hemagglutinin shedding was observed.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Bordetella pertussis possesses surface antigens crucial for serotyping and virulence.
- Fimbriae are important surface structures involved in bacterial adhesion and immune evasion.
- Understanding antigen distribution on B. pertussis is vital for vaccine development and pathogenesis studies.
Purpose of the Study:
- To investigate the localization and co-expression of specific antigens (agglutinogens 2 and 3) on Bordetella pertussis fimbriae.
- To examine the surface association of filamentous hemagglutinin (FHA) and lymphocytosis promoting factor (LPF) with B. pertussis cells.
Main Methods:
- Immuno-electron microscopy utilizing colloidal gold-tagged monoclonal antibodies (McAbs).
- Double labeling experiments to detect co-localization of antigens on individual fimbriae.
- Analysis of antigen distribution on both fixed and unfixed B. pertussis cells.
Main Results:
- McAbs against agglutinogens 2 and 3 demonstrated serotype-specific labeling of fimbriae.
- Double labeling suggested potential co-occurrence of antigens 2 and 3 on individual fimbriae.
- Filamentous hemagglutinin was found to shed readily from unfixed cells but formed aggregates on fixed cells.
- Lymphocytosis promoting factor appeared more closely associated with the cell surface than FHA.
Conclusions:
- Specific monoclonal antibodies effectively map Bordetella pertussis surface antigens, particularly on fimbriae.
- Evidence suggests co-expression of agglutinogens 2 and 3 on the same fimbriae.
- Filamentous hemagglutinin exhibits dynamic surface association, influenced by cell fixation.
- Further investigation into LPF's surface association is warranted.