One-shot flu vaccine in the offing

Scientists have discovered flu- fighting white blood cells in our noses that can stop the virus from reaching the lungs, a finding that may pave the way for a one-shot vaccine against various types of infuenza.
Researchers from University of Melbourne in Australia started by looking at a particular white blood cell - the resident memory CD8 T cells or Trms.
Located in the lungs, the Trms are excellent at protecting against different strains of flu, researchers said.
The flu vaccine most people get each year works by stimulating white blood cells to produce the antibodies to fight a specific infection, researchers said.

However, resident memory T cells, take up residence in and around organs, rather than living a roving life in the bloodstream, they said.
"We had identified a cell type that could provide great protection against different strains of influenza virus, but because they decayed so rapidly we would still have to constantly vaccinate the population," said Angela Pizzolla, research fellow at University of Melbourne.

Researchers then found a population of Trms living in nasal tissue that and unlike their counterparts in the lung, they can live for a very long time.
They tracked these cells in lung and nasal tissue and found that while a population of lung Trms cells would drop at rate of 100,000 cells down to just 1000 cells over a period of 100 days, the Trms cell population in the nasal tissue remained stable.

This meant that the flu-fighting cells in the nasal tissue can potentially disable the inhaled influenza virus in the nose and upper airways, preventing the infection from reaching the lungs, researchers said.
It also means scientists could look at developing a vaccine that stimulates these Trms in the nose, halting specific strains of virus before it even enters the respiratory system, they said.
"We basically stopped influenza at the gates," said Linda Wakim from University of Melbourne.
The influenza virus is notoriously difficult to treat and manage. It is highly contagious - meaning it is very good at spreading from person to person.

This is a big problem for influenza vaccine development. Our current flu vaccines work by training the body to recognise a component on the surface on an influenza virus particle, researchers said.
"Instead of recognising external parts of the virus, which are constantly changing, these cells are trained to recognise internal parts of the virus. These parts of the virus are equivalent to our internal organs," Wakim said.
It means a vaccine that induces flu fighting Trm cells in the nose could outwit the flu virus, researchers said.
The study was published in the journal Science Immunology.