Researchers have found that on infecting 41 healthy volunteers with different strains of flu virus, those with higher levels of a specific type of white blood cell were less likely to develop severe illness. Now the team of researchers hopes to mimic the natural resistance shown by some of the volunteers, by creating a vaccine that boosts levels of a particular subset of the 'T-cells'.
Researchers at Oxford and Southampton universities and Retroscreen Virology explained that these cells are able to identify proteins, called peptides that are found inside almost all known flu viruses. Results of the study are published in Nature Medicine.
Dr Tom Wilkinson, from Southampton University, said the study was the first to cleanly “map” individuals' immune response, by infecting them and then keeping them “quarantined” in sterile conditions. He said, “If we can expand the population of these T-cells in people using a vaccine, which is perfectly feasible, we could protect against all flu strains.”
Several institutes around the world are trying to develop a universal vaccine, conscious of the looming threat that the H5N1 avian flu strain could mutate and start spreading from human to human. Current vaccines only work for a few seasons because they stimulate antibodies which attach to sites on the shells of viruses, which mutate rapidly.
A T-cell vaccine aimed at the molecules has the potential to provide long-term immunity against all major flu strains, including seasonal, avian (bird) and swine viruses.
Co-author Professor Sir Andrew McMichael, director of the Medical Research Council Weatherall Institute of Molecular Medicine at Oxford University, said, “Current flu vaccines are very good at producing antibodies against flu, but not so good at generating a lasting immunity involving T-cells. The big question is: if we had a pandemic involving a much more severe virus than the swine flu we saw, what would we do in the six months it takes to develop an effective vaccine? This study suggests that vaccines stimulating a T-cell response might be an option, but there remains a lot to do to be certain of this approach.”
Past flu pandemics have caused disaster on a global scale. The 1918 Spanish Flu pandemic killed up to 40 million people, more than the number who died in the First World War. Britain's last pandemic outbreak of swine flu in 2009 claimed 457 lives. Experts believe more severe pandemics may occur in the future, possibly as a result of a mutated avian (bird) flu strain.
Inovio Pharmaceuticals said Tuesday that it is moving closer to a universal vaccine against flu as animal studies showed protective antibody immune responses against multiple H3N2 and Type B strains. The H3N2, H1N1, and Type B influenza strains represented in each year’s seasonal influenza vaccine are updated annually, but only protect against a single strain within each of these subtypes.
The new flu data was highlighted by Inovio's Chief Medical Officer, Dr. Mark Bagarazzi, in a presentation and panel session at Phacilitate Vaccine Forum Washington 2012.
“These new data for H3N2 and Type B in animal models further validate our strategy to develop a universal vaccine to prevent known and unknown influenza strains, as well as our entire SynCon platform,” said Inovio's president and CEO, Dr. J. Joseph Kim.
Study shows potential for universal flu vaccine with broad antibody response