Despite this clear therapeutic success, and in spite of important changes in preventive hygiene and new guidelines designed to avoid contamination in CF Centers, during CF camps and meetings among patients with and without Pseudomonas aeruginosa infection, there is intense interest in the development of vaccines for the prevention of infections of the lungs with P. aeruginosa.

In order to provide a good immunological response, such as is available with other vaccines against bacterial infections, such as diphtheria and tetanus, several parts of the Pseudomonas aeruginosa cell body have been identified as potential candidates for producing an efficient vaccine. The elements of the outer membrane proteins, OMP, the so-called hairs, pili, the proteic part of the locomotion apparatus, the flagellum, and, more recently, translocation proteins related to the secretive activity of P. aeruginosa are of particular interest.

All the above proteins, that are potentially efficient in an antibody stimulating vaccination, are still the objects of preliminary studies.

Another possible vaccine starting point is an element of the P. aeruginosa surface which is called lipo-poly-saccharide (lipo = fat, poly = multiple, saccharide = sugar), LPS. This element of P. aeruginosa is known to stimulate high affinity antibodies which protect the lung against this part of the P. aeruginosa surface. High affinity means that there is a strong attraction between the above-mentioned LPS and the newly stimulated antibodies which will possibly destroy the bacteria (see figure 1).
To achieve induction of these high affinity antibodies (highly efficient antibodies) a team from the company Berna Biotech Ltd. Berne, and the CF Center, Department of Pediatrics, University of Berne initiated a clinical trial in cystic fibrosis patients in 1989. The evaluations of results after 1, 3 and 4 years showed safety and the capacity of the vaccine to stimulate a good antibody-response, that is, the vaccine tested in the trial produced a good immune response in CF patients who received the vaccine.

As the first vaccine against P. aeruginosa lung-infections in the world, this development may well signify a great advance in the anti-infection therapy of CF. Unfortunately it will not mean that we will definitely be free from this resistant and devastating bacterial infection as a result of using this vaccine. In the best case scenario it may complement the strategy of classical CF lung-therapy, represented by inhalation of bronchodilators, followed by chest-physiotherapy and expectoration (2 -3 times a day) and if necessary coupled with inhalations of DNASE and/or antibiotics (tobramycin). Without these pre-requisites the vaccine approach alone, cannot achieve the best possible outcomes for individuals with CF.

How to use the vaccine in CF patients without P. aeruginosa infection and the timing of the application of booster vaccinations are questions that still remain to be answered. They will not be settled before the end of the ongoing multicenter study, hopefully to be reported in 2006.


Fig. 1.


Fig. 2.