Related Experiment Videos
Type-4 pili and meningococcal adhesiveness
1Laboratoire de Microbiologie, INSERM U411, Faculté de Médecine Necker-Enfants Malades, Université René Descartes, Paris, France. nassif@necker.fr
Abstract:
The ability to interact with non-phagocytic cells is a crucial virulence attribute of the meningococcus. Pili play a major role in this process and are the only means yet discovered by which capsulated bacteria may adhere to cells. Pilus-mediated adhesion is a two-step process which requires (i) the expression of the adhesin PilC1 and (ii) the expression of an appropriate pilin variant. Some pilin variants have the ability to modify the degree of adhesiveness through the formation of bundles of pili which increases bacteria-bacteria interactions.
Insights
Meningococcus uses pili, hair-like structures, to adhere to host cells, a key step in infection. Specific pili variants and adhesins control this bacterial adhesion process.
Area of Science:
- Microbiology
- Bacterial pathogenesis
- Cell-adhesion mechanisms
Background:
- Neisseria meningitidis (meningococcus) possesses critical virulence factors enabling interaction with non-phagocytic host cells.
- Pili are identified as the primary structures mediating bacterial adhesion to host cells, particularly for encapsulated bacteria.
- Bacterial adhesion is essential for colonization and the initiation of infection.
Purpose of the Study:
- To elucidate the role of pili in meningococcal interaction with non-phagocytic cells.
- To identify the specific components and processes involved in pilus-mediated bacterial adhesion.
- To understand how different pilin variants influence bacterial adherence and aggregation.
Main Methods:
- Investigated the expression of adhesin PilC1 and various pilin variants in meningococcus.
- Analyzed the mechanism of pilus-mediated adhesion as a two-step process.
- Examined the impact of pilin variants on the formation of pili bundles and bacteria-bacteria interactions.
Main Results:
- Pilus-mediated adhesion is dependent on the expression of adhesin PilC1 and specific pilin variants.
- Certain pilin variants facilitate the formation of pili bundles, enhancing bacteria-bacteria interactions.
- Pili are the sole identified mechanism for capsulated bacteria to adhere to host cells.
Conclusions:
- Pili are essential for meningococcal virulence, enabling adherence to non-phagocytic cells.
- The adhesion process is regulated by the interplay between PilC1 adhesin and specific pilin types.
- Modulation of pili structure by variants influences bacterial aggregation and host cell interaction.