Study gives tool to scientists studying flu vaccines

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Study gives tool to scientists studying flu vaccines

Researchers compile 'a huge resource'

By Bruce Lieberman, UNION-TRIBUNE STAFF WRITER January 2, 2007

Scientists still have huge gaps in their knowledge of the flu virus, a

disease that kills 36,000 Americans each year, a new study shows.

The examination by San Diego researchers is the most comprehensive to

date on what scientists know about antibody and T-cell epitopes for

the influenza A virus. Antibody epitopes and T-cell epitopes are the

sites on the surface of the flu virus that are recognized by the

immune system.

The paper is published online this week in the journal The Proceedings

of the National Academy of Sciences.

More insights are needed about these epitopes before scientists can

develop better vaccines against the world's broad array of influenza A

viruses – the most common type of flu virus and the cause of the most

serious epidemics in history. The avian flu, H5N1, is an influenza A

virus.

The study " gives researchers ways of sharing knowledge and information

never available before, " said Alessandro Sette, director of the Center

for Infectious Disease at the La Jolla Institute for Allergy and

Immunology and one of the study's authors.

" It's a huge resource to speed up things. "

Scientists at the institute examined a compilation of studies of 58

influenza A strains that detailed 600 antibody and T-cell epitopes.

One goal of the study was to identify how many epitopes were common to

the strains.

" If we can find shared epitopes, it may be possible to develop an

influenza vaccine with greater cross-protection for many different

viruses, " Sette said.

The study found hundreds of epitopes that are similar from strain to

strain. But it remains to be seen whether they are similar enough to

be a target for a new vaccine.

Of all 600 epitopes studied, only one appears to be ideal for a

vaccine that would be effective against multiple strains, the

scientists said.

Several areas of research have not received enough attention, the

scientists found.

Most influenza research is based on flu strains maintained in the lab,

rather than wild influenza strains.

" Since we know the virus mutates, research needs to be done using

influenza strains currently circulating in the population, " said

, chief technology officer for the La Jolla Institute

for Allergy and Immunology.

Furthermore, most influenza epitope studies have been conducted in

mice. Only one of the antibody epitopes detailed in studies around the

world is a site that the human immune system targets.

Experimenting with the flu virus in humans poses ethical problems, but

scientists said they need more information about how the human immune

system responds to the virus – not just how the immune systems of

animals respond.

During the analysis, the scientists also found that few of the 600

epitopes studied around the world are sites found on the avian flu

virus, H5N1.

" To develop vaccines against avian flu, we need all the information we

can get, " said.

The information that the flu study examined was part of a database

constructed by the La Jolla Institute for Allergy and Immunology. The

database, funded in 2004 by a $25 million contract with the National

Institutes of Health, is intended to catalog everything that's known

about epitopes for all infectious diseases – not just influenza.

Called the Immune Epitope Database and Analysis Resources Program, the

project places particular emphasis on emerging infectious diseases,

such as West Nile virus, and diseases the government considers

potential terrorist threats.

The NIH directed the La Jolla institute to study the influenza virus

first, given the global health concerns about avian flu.

" This study is interesting for what it shows we know and do not know, "

said S. Fauci, director of the National Institute of Allergy

and Infectious Diseases, the NIH division that awarded the 2004 grant.

" It reveals many gaps in our knowledge . . . and where we need to

focus our attention. "

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