Research into how Salmonella bacteria cause infection is leading to safer, more effective vaccines against typhoid and other diseases, scientists heard today at the spring meeting of the Society for General Microbiology at the University of Warwick in the UK.Dr. Pietro Mastroeni of Cambridge University said, "We have been studying the many ways in which new generations of live attenuated vaccines protect against disease. Producing an immune response against an infectious bacterium or virus is not always enough to give protection, and in some cases can worsen the disease."
A big challenge in vaccine design is how to trigger a protective immune response with the safest possible vaccine.
Vaccine-induced immunity requires a sophisticated cross-talk between different parts of the immune system. Long-lasting immunity relies on the presence and activation of species-specific T- and B-cells. Both T-cell and B-cell dependent immunity is needed to clear bacteria from tissues.
"This research is leading to more rational strategies to fight Salmonella infections in man and domestic animals. By introducing proteins from different micro-organisms we can also use Salmonella as a delivery vehicle to protect against other diseases," Dr. Mastroeni said.
"Recent advances in DNA technology and genetic information have led to new approaches in which to safely modify the Salmonella genome. We now have vaccine strains that can induce solid immunity after only one dose without significant side effects," Dr. Mastroeni added.
Salmonella typhi causes typhoid fever in humans, leading to 16 million cases (600,000 deaths) worldwide each year. Other Salmonella species cause foodborne disease.
There were about 17,000 cases of Salmonella food poisoning reported in the UK in the year 2000 and twice as many were reported in the year 1998. An increasing number of clinical isolates are multi-antibiotic resistant and so are difficult to treat with existing drugs.
The Society for General Microbiology is the largest microbiology society in Europe, and has over 5,500 members worldwide. The Society provides a common meeting ground for scientists working in research and in fields with applications in microbiology, including medicine, veterinary medicine, pharmaceuticals, industry, agriculture, food, the environment and education.
(Editor's Note: Part of today's presentation, "The development of vaccine-induced host resistance to salmonella: macrophage functions, cytokine networks, T- B-cell interactions," has been published in Infection and Immunity [2002 Feb; 70(2): 5517]; Science [2000 Mar 3; 287(5458): 16558)]; and the Journal of Experimental Medicine [2000 Jul 17; 192(2): 23748].)
Related website:
Society for General Microbiology meeting page
[Contact: Dr. Pietro Mastroeni]
09-Apr-2002
