September 23, 2013
Researchers Inch Closer To Universal Flu Vaccine
[ Watch the Video: From Pandemic To A Universal Flu Vaccine ]
Lee Rannals for redOrbit.com - Your Universe Online
Scientists at the Imperial College London are getting closer to developing a universal flu vaccine after using the 2009 pandemic as a natural experiment.
The team wrote in the journal Nature Medicine that they collected blood samples in 2009 when the swine flu pandemic was getting underway. These volunteers who donated their blood also reported any symptoms they experienced over the next two flu seasons. With these samples, the team found that those who avoided severe illness had more CD8 T cells in their blood at the start of the pandemic.
The team recruited 342 staff and students at Imperial in 2009 during the swine flu pandemic. The volunteers sent emails every three weeks with answers about their health. They also sent in a nasal swab back to the lab if flu symptoms began to occur.
Scientists believe a vaccine that stimulates the body to produce more of these cells could be effective at preventing flu viruses, including any new strains that could pop up and crossover into humans to cause serious disease.
"New strains of flu are continuously emerging, some of which are deadly, and so the Holy Grail is to create a universal vaccine that would be effective against all strains of flu," said lead author Professor Ajit Lalvani from the National Heart and Lung Institute at Imperial College London in a statement.
Flu vaccines make the immune system produce antibodies that recognize structures on the surface of the virus to prevent infections. These vaccines are usually a step behind the evolving virus as they have to be changed each year due to new viruses with different surface structures.
Experimental models show that T cells may protect against flu symptoms, but scientists have not tested this ideas in humans until now. The team found that those who fell ill more severely with flu had fewer T cells in their blood than those with no flu symptoms.
"The immune system produces these CD8 T cells in response to usual seasonal flu. Unlike antibodies, they target the core of the virus, which doesn't change, even in new pandemic strains. The 2009 pandemic provided a unique natural experiment to test whether T cells could recognize, and protect us against, new strains that we haven't encountered before and to which we lack antibodies," Lalvani said.
"Our findings suggest that by making the body produce more of this specific type of CD8 T cell, you can protect people against symptomatic illness. This provides the blueprint for developing a universal flu vaccine."
He said they already know how to stimulate the immune system to make CD8 T cells by vaccination. The team plans to design a vaccine in order to help prevent people getting symptoms and transmitting the infection to others.