Using peptides to block the flu....

Every year, scientists scramble to predict which version of the influenza virus will predominate so they can produce that year's flu vaccine. And every year, people need to get the new vaccine to ward off the flu. These

complications arise because influenza strains constantly mutate parts of themselves, presenting new targets to the immune system. Now, Japanese researchers are examining small, unchanging parts of the virus to find ways of protecting against many different flu strains.

Kazumasa Ogasawara and his colleagues at Hokkaido University in Sapporo, Japan, created a vaccine by inserting a peptide consisting of seven amino acids from the unchanged hemagglutinin protein of the flu virus into a protein capable of binding to immune cells that fight infection. The researchers then treated mice with either the seven-amino-acid peptide or the peptide vaccine and exposed them to strains of influenza from the past 10 years.

Mice that received the peptide-only treatment got influenza symptoms. But the mice that got the peptide vaccine produced antibodies that neutralized all varieties of influenza. The animals "were 100 percent protected from the disease," says Ogasawara.

However, the mice remained immune for only 2 weeks; after that, they needed a vaccine booster. Ogasawara notes that the effects of the vaccine will need to be longer-lived before it can provide practical protection for humans.