A team of researchers from the University of California, San Diego, has found that immunization with a stabilized version of a protein on Streptococcus bacteria can protect against Strep infections, from which more than 600 million of people suffer each year and 400,000 even die.

In the March 7 edition of the journal Science, the researchers describe, for the first time, the detailed structure of the little piece of bacteria that causes serious illnesses including strep throat, rheumatic fever and the life-endangering “flesh-eating” syndrome called necrotizing fasciitis.

It was difficult to design a vaccine against Group A Streptococcus (GAS), as the piece of bacteria that is easily identified by the immune system is also the most dangerous. It causes inflammation and heart damage. But the team of researchers managed to produce a version of the protein which can make the immune system stronger, without the dangerous side effects of the standard M1 protein.

"Using X-ray crystallography, we determined that M1 protein has an irregular, unstable structure," explained Partho Ghosh, a professor of chemistry and biochemistry in UCSD's Division of Physical Sciences, according to Science Daily. "We created a modified version of M1 with a more stable structure, and found that it is just as effective at eliciting an immune reaction, but safer than the original version of M1, which has serious drawbacks to its use in a vaccine."

Vaccines use antigens to make the immune system to react against infections invading the body, by teaching immune cells to look for certain structures or proteins.

Two successfully used vaccines against other types of strep are Wyeth's Prevnar, given to babies in many countries and Merck & Co's Pneumovax, given to adults.