Figure 1.

The role of PptB in mediating meningococcal dissemination. (A) Bacteria growing on the epithelial cell surface in microcolonies are induced to express PptB after host cell contact, which induces addition of phosphoglycerol (PG) onto pilin subunits. (B) Bacteria whose pili have been PG-modified lose their aggregative properties due to loss of pilus bundling, and begin to detach from the microcolonies. Detached bacteria can then move to different sites within the same host, or be transmitted to new hosts.