By Robert Roos, News Editor
Apr 11, 2011 (CIDRAP News) – A team of US researchers recently added to the evidence that humans can and do produce antibodies that target a wide range of influenza strains, though how the findings can be exploited in the quest for a “universal” flu vaccine remains to be seen.
The researchers tested serum samples from participants in an H5N1 flu vaccine study and also looked in a commercial preparation of intravenous immunoglobulin (an antibody preparation made from blood plasma and used to treat certain diseases). In both cases they found low levels of broadly neutralizing influenza A antibodies, including antibodies covering both of the major influenza A groups.
“These data—to our knowledge, for the first time—quantitatively show the presence, albeit at low levels, of two populations of heterosubtypic BnAbs [broadly neutralizing antibodies] against influenza A in human serum,” says the report in the Apr 15 issue of Clinical Infectious Diseases (CID). The research team included members from several institutions in Boston; La Jolla, Calif.; and the National Institute of Allergy and Infectious Diseases in Maryland.
In an accompanying CID editorial, two leading flu experts from the Centers for Disease Control and Prevention (CDC) called the findings “auspicious” for the development of a universal flu vaccine.
Flu vaccines now in use target the head of the flu virus’s hemagglutinin (HA) protein, which evolves rapidly to evade the immune system, producing an ever-shifting spectrum of viral strains. Consequently the vaccine is reformulated each year in an effort to match the circulating viruses.
The prime goal of flu vaccine researchers is to develop a vaccine that targets a more stable region of the virus, so that one dose could provide protection against many strains and last many years.