Group B Streptococcus - commonly called GBS - is a disease-causing bug that comes in a number of variations, which has made it difficult to produce a useful vaccine. Now, by screening the genome of several subtypes of the bacterium, scientists have come up with a ‘universal’ GBS vaccine.

GBS is the most common cause of life-threatening bacterial infections in newborns. In most cases it is acquired from the mother during the birth process. While various vaccines against GBS are now being tested in clinical trials, they only offer protection against the most common strains in the US, not against subtypes encountered in other parts of the world.

To develop a GBS vaccine that provides broader protection, Dr. Guido Grandi, from Chiron srl in Siena, Italy, and colleagues analyzed the genetic make-up of eight GBS subtypes. From this, they identified and tested 312 GBS surface proteins that might serve as vaccine components.

Four proteins appeared to play a key role in triggering an immune response, the researchers report in the journal Science. Alone, each antigen elicited strong protection in mice against corresponding GBS strains. Combined into one vaccine, the proteins provided strong protection against a wide range of GBS strains.

This approach “provides the basis for the potential development of universal protein-based vaccines against other important and highly variable pathogens, such as Group A Streptococcus and Streptococcus pneumoniae,” the researchers point out.

SOURCE: Science, July 1, 2005.