The researchers then discovered that the protein underwent various modifications over time. One of these, in particular, has proved more interesting than the others: The addition of a phosphoglycerol. This chemical group once grafted onto the pilin, gives the signal for dissemination.
Bacteria isolated from the colony depart as "scouts"
Following these initial results, the researchers discovered the presence of a gene which enabled the transfer of phosphoglycerol onto the pilin: the gene, pptB. This gene only becomes fully functional when the bacteria is in contact with the cells lining the wall of the throat. The frantic activity of the pptB gene causes the addition of phosphoglycerol to the pilin. This then loses one of its essential properties: its capacity to form aggregates. As a consequence, some of the bacteria detach themselves from the colony and, little by little, are disseminated. This strategy is used by the bacteria in order to colonize other areas of the throat and to cross the cells lining it. "This phenomena could almost be compared with the formation of metastases in cancer", says Guillaume Dumnil.
This is the first time that scientists have been able to accurately identify the chain of events which controls the bacteria in the bloodstream. It is a first step. "We now know how the Neisseria meningitidis passes from the throat into the blood. We hope to be able to demonstrate that an identical process is involved when the bacteria passes from the blood into the brain, instigating meningitis", concludes Guillaume Dumnil.
Furthermore, if the researchers were able to find molecules which can block this dissemination, they would have both a preventative tool (blocking colonization from the throat and passage into the bloodstream) and a therapeutic tool (limiting colonization from the blood vessels and transmission
|Contact: Sverine Ciancia|
INSERM (Institut national de la sant et de la recherche mdicale)