`Seek and destroy` vaccines for meningitis outdated

The ability of meningococci bacteria to change their cell surface proteins could reduce the effectiveness of the current meningitis C vaccine. Now scientists are working on vaccines that would allow us to co-exist happily with these microbes, according to research presented today (Monday 08 April 2002) at the spring meeting of the Society for General Microbiology at the University of Warwick.

“We have identified several proteins secreted by meningococci, which are involved in causing disease but which do not prevent the bacteria from living and reproducing in the body. By including secreted proteins in a vaccine we may avoid the strong selective pressures that cause meningococci to mutate so quickly,” says Dr Del Ala’Aldeen of the University Hospital of Nottingham.

Dr Ala’Aldeen explains, “We have shown that meningococci disguise themselves by changing their coat proteins while carried in the throat, which allows them to avoid being detected by the immune system. There is genuine concern that such escape among Group C meningococci may result from the strong selective pressure applied as a result of mass vaccination.”

“It is possible that we may never be able to eradicate organisms such as meningococci or even reduce their circulation in the community. Our approach relies on targeting antigens that are largely secreted and are important in invasion (and disease) but do not affect colonization. This way we might eliminate or reduce invasive disease, and accept an eternal co-existence with meningococci bacteria,” says Dr Ala’Aldeen.