Genome screen speeds scientists’ vaccine search

WASHINGTON – Scientists hunting a vaccine to protect newborns from a severe infection not only found a promising candidate; they developed a new way to speed the search for vaccines against other hard-to-fight diseases, too.

It’s a gene-searching technique that goes by the humble name “multiple genome screen.” But the research, led by Chiron Corp., elicited a “wow” from the government’s infectious disease chief.

“It opens up a new arena” in developing vaccines against multiple strains of diseases, said Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases. “This is a very, very elegant, potentially usable avenue to go after that whole concept of universal vaccines.”

The first candidate: a possible vaccine against Group B strep, a germ that lurks harmlessly in many women’s bodies but that can be fatal or brain-damaging if passed to their infants during birth.

So far, the experimental vaccine has been tested only in mice. But studies reported Thursday in the journal Science suggest it’s the first candidate in two decades that might protect against all major strains of Group B strep. Chiron’s lead researcher says the company is discussing with U.S. regulators how to begin human testing.

Group B streptococcus, a cousin of the germ that causes strep throat, is found in up to 40 percent of women. It usually causes them no symptoms. But it’s the most common cause of blood infection and meningitis in newborns.

There are numerous strains of the germ, and previous attempts at vaccines couldn’t offer universal protection.

Enter the new genetic technique.

Instead of laboriously growing the bacteria in laboratory dishes the scientists used computers to rapidly identify all the genes in eight major strains of Group B strep.

First they teased out genes shared by all the strains, said Herve Tettelin, a molecular biologist with the Institute for Genomic Research, a Rockville, Md., nonprofit group that collaborated with Chiron.

Then they identified additional genes that produce proteins on the germs’ surface – easy for the immune system to spot and thus important for a vaccine, he explained.

The vaccine proved 87 percent protective.