Your Nose Hides a Robust Germ Defense System

How did we miss an army of germ-fighting warriors camped out on our very faces?. mark.dark.9000/Shutterstock

Surely by now science has uncovered all of the innermost workings of the humble nose.

It is, after all, our most front-and-center organ, navigating the subtlest details of our world one whiff at a time.

The nose keeps us grounded, playing a vital role in easing anxiety and fortifying memory. We even have an idea why it has evolved to look the way it does.

But it turns out the nose knows a few billion more secrets.

New research from the Massachusetts Ear and Eye Infirmary suggests that cells in our nasal passageway form a powerful antibacterial brigade.

When we inhale bacteria, researchers found, nasal cells secrete tiny fluid-filled sacs called exosomes, which attack the intruder like a swarm of angry wasps.

"Similar to kicking a hornet's nest, the nose releases billions of exosomes into the mucus at the first sign of bacteria, killing the bacteria and arming cells throughout the airway with a natural, potent defense," senior author Benjamin S. Bleier noted in a press release.

The exosomes also deploy antimicrobial molecules to areas further down the nasal passageway.

"It's almost like this swarm of exosomes vaccinates cells further down the airway against a microbe before they even have a chance to see it," Bleier adds.

Mucus: An unlikely hero

Man blowing his nose
We spend a lot of our lives trying to expel mucus from our bodies, but mucus keeps harmful pathogens out of our mouth, throat, lungs, intestines and nose. Syda Productions/Shutterstock

We can thank another largely unheralded hero for its part in the war on germs: mucus. Those swarming exosomes ride a wave of mucus to ward off the threat in the nose.

Let's face it, mucus doesn't get the respect it deserves. We spend a lot of our lives trying to unceremoniously expel it from our bodies by whatever means necessary. But thankfully, it just keeps coming back. In fact, mucus covers more than 4,000 square feet of surface area, or, as Medical News Today points out, about enough to pave a basketball court.

And that's a good thing, because all that mucus keeps harmful pathogens out of our mouths, throats, lungs, intestines — and, thanks to the newly discovered exosomes — our noses.

For their experiments, researchers at Massachusetts Ear and Eye grew cells from the mucus of patients. They then simulated an exposure to bacteria.

Not only did the number of exosomes double, but they also released unique antibacterial molecules to reinforce the rest of the nasal passageway against the threat.

The exosomes, scientists found, were at least as effective as antibiotics at killing the bacteria.

The nose knows

An illustration of the nasal passageway
When marauding germs come knocking at the nose, tiny sacs called exosomes rise to the occasion. CLIPAREA l Custom media/Shutterstock

While there's plenty of evidence suggesting our bodies are constantly on the lookout for germs — even our skin is designed as a physical bulwark against them — the nasal defense corps has gone about its business largely under the radar.

But there's no telling how many daily threats from pathogens like viruses, toxins, parasites and fungi your nose has stamped out long before they become a problem.

And, researchers say, there's even more our nose might teach us — like how to harness its transport system to deliver certain treatments more effectively.

The exosomes, for example, could be an effective means for sending drugs into the upper airway and maybe even deeper into the body.

"The nose provides a unique opportunity to directly study the immune system of the entire human airway — including the lungs," Bleier notes.