By Imogen Howse via SWNS
Scientists have discovered ‘lung flu fighters’, the virus-eating cells which rush into our lungs to help us fight the flu.
These immune cells – called macrophages – destroy bacteria, viruses, and any cells that appear ‘foreign’, such as cancerous cells, giving our bodies a better chance at tackling disease.
Macrophages were found in the fluid-filled sac around the lungs, which came as a surprise to scientists who initially thought the sac functioned to protect our lungs from external damage.
Instead, they found it also houses these important immune cells which, during a flu infection, cross over into the lungs and work to reduce levels of disease.
The research team from California, initially set out to understand which types of cells are present in the lungs when a person has the flu.
They took existing data on lung-related genes from studies of mice that either survived the flu or died from it, and used an algorithm to predict the cell types that change in the lungs during infection.
Through this process, they discovered that macrophages were moving into the lungs.
“The name macrophage means ‘big eater’,” said Juliet Morrison, a virologist and professor at the University of California, Riverside.
“They gobble up bacteria, viruses, cancer cells, and dying cells. Really, anything that looks foreign, they take it up and destroy it.
“We were surprised to find them in the lungs because nobody has seen this before – that these cells go into the lung when there is an infection.”
Professor Morrison and her team then tried to establish the role the macrophages play by removing them from the lungs during infection.
Results, published in the journal Proceedings of the National Academy of Sciences, revealed that this resulted in more lung inflammation and a bigger presence of disease.
Essentially, the macrophages were reducing inflammation and fighting the infection.
“Our study shows that it’s not just what happens in the lung that matters, but also what’s outside the lung,” Prof Morrison said.
“Cells not normally connected to the lung can have impacts on lung disease and lung health.”
The team from UC Riverside said their next steps will be to determine which proteins ‘tell’ the macrophages to move into the lungs.
Once the signals have been identified, it may be possible to create drugs that boost the number or activity of macrophages – and therefore help the body fight the flu.
“The strategy of boosting human defenses to infection, rather than developing another antiviral, could offer people a flu treatment that would be effective for much longer,” Prof Morrison explained.
This approach has become of more interest to scientists recently due to the growing issue of antibiotic and antiviral resistance – something that happens when bacteria and viruses develop the ability to defeat the drugs designed to kill them.
According to the Centers for Disease Control and Prevention, more than 2.8 million drug-resistant infections occur each year in the US – with more than 35,000 people dying as a result.
“Misuse and overuse of drugs is accelerating this problem,” Prof Morrison said.
“But if we can boost what resolves infection in us, we’re less likely to have resistance.
“The immune system is so complicated, but it’s our best bet in the long run to work with what we have rather than chase viruses that continue to escape our therapeutics.”
