Universal flu vaccine comes closer to reality

Every year, many people roll up their sleeves for a flu shot. Howbeit, the influenza virus has thousands of strains and the vaccine can't guard against all of them. But now, a team of researchers finally might be onto something.

Scientists at the National Institutes of Health (NIH) have identified three types of vaccine-induced antibodies that can neutralize diverse strains of influenza virus that infect humans.

The discovery will help guide development of a universal influenza vaccine, according to the investigators.

Until now, scientists had only identified broadly neutralizing antibodies targeting the flu virus stem in humans following natural infection. The new research provides clear evidence that these antibodies can be induced by a vaccine.

The researchers examined blood samples from six people who had received a vaccine against H5N1 influenza, commonly known as the bird flu virus.

In the blood samples they identified B cells (a type of white blood cell that responds to infection by secreting antibodies) that reacted to various subtypes of influenza virus, and then characterized and classified the cells' antibody genetic sequences.

The scientists discovered the B cells encoded three classes of antibodies seen among multiple participants that can neutralize diverse influenza virus subtypes and, therefore, could form the basis of a universal flu vaccine.

Researchers can now use the B cell sequencing information they identified to quickly and accurately measure immune responses among participants in future influenza vaccine trials, according to the authors.

The findings appear online in the journal Cell.