FOR IMMEDIATE RELEASE
Monday, Nov. 16, 2009
A new study shows that molecular similarities exist between the 2009 H1N1 influenza virus and other strains of seasonal H1N1 virus that have been circulating in the population since 1988. These results suggest that healthy adults may have a level of protective immune memory that can blunt the severity of infection caused by the 2009 H1N1 influenza virus.
The study team was led by Bjoern Peters, Ph.D., and Alessandro Sette, Ph.D., of La Jolla Institute for Allergy and Immunology, Calif., grantees of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.
The investigators looked at molecular structures known to be recognized by the immune system—called epitopes—on 2009 H1N1 influenza and seasonal H1N1 viruses. Viral epitopes are recognized by immune cells called B and T cells: B cells make antibodies that can bind to viruses, blocking infection, and T cells help to eliminate virus-infected cells.
Using data gathered and reviewed from the scientific literature and deposited into the NIAID-supported Immune Epitope Database and Analysis Resource (www.iedb.org), the investigators found that some viral epitopes are identical in both the 2009 and seasonal H1N1 viral strains. Those epitopes that could be recognized by two subsets of T cells, called CD4 and CD8 T cells, are 41 percent and 69 percent identical, respectively. Subsequent experiments using blood samples taken from healthy adults demonstrated that this level of T-cell epitope conservation may provide some protection and lessen flu severity in healthy adults infected with the 2009 H1N1 influenza virus.
Analysis of the database also found that among six viral surface epitopes that can bind antibody, thereby preventing infection, only one is conserved between 2009 and seasonal H1N1 viral strains.
These results suggest that healthy individuals may have immune memory that recognizes the 2009 H1N1 strain and therefore can mount some measure of an immune attack. The findings also may help explain why the 2009 H1N1 influenza pandemic affects young children more severely than it does healthy older adults and also why two H1N1 vaccinations are needed to protect children ages nine years and under.
NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of
infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News
releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at www.niaid.nih.gov.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S.
Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research,
and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
NIH...Turning Discovery Into Health ®
back to top
Last Updated November 16, 2009