Microscopic secrets of your immune system

Short of cursing it when we catch a cold, most of us don’t give much thought to our immune system. But now, the molecular and cellular activity that usually trundles along unnoticed has been brought to light in an extravagant exhibition of microscope images captured by scientists for tomorrow’s International Day of Immunology.

“These microscopy images allow us to delve inside the body and see the different locations where the immune system is present,” said Gabriela Khoury, an immunologist at Monash University in Melbourne, Australia, and the exhibition organiser.

“They can be appreciated on a scientific level and also as a form of abstract art.”

Feast your eyes on our five favourites.

Skin deep immunity

Whether wrinkly or smooth, freckled or olive, your skin is a bustling hive of activity. As the first line of defence against billions of invading pathogens, the skin’s job is to form a solid fort.

The image above was created by Maverick Lau from Melbourne’s Monash University. By cutting skin tissue to a sliver 50 times thinner than a human hair, Lau could illuminate individual hair follicles (blue) concentrated near damaged skin, with some sprouting hairs (green).

A goblet to calm the gut

Like skin, the gut lining is a border between you and the environment. With a surface area of around a tennis court, your intestinal epithelium keeps the immune system busy defending against any pathogens which hitch a ride with food.

When the gut’s immune system switches to overdrive, it can produce chronic inflammation and cause diseases such as ulcerative colitis or Crohn’s disease. In the image above, we can see Goblet cells (green) spotted along the colon (red). These cells produce mucous which can protect the intestine from aggressive inflammation.

Melanoma’s battleground

With more than 130,000 melanomas diagnosed worldwide each year, Heloise Halse at Melbourne’s Peter MacCallum Cancer Centre is shining a spotlight on how the skin cancer evades the immune system.

To create this image, Halse stained cells near a melanoma spot in different colours. Immune cells called T cells (yellow and red) and B cells (white) are poised to take out the diseased melanoma cells (purple). But the melanoma’s defence is glowing turquoise – a protein called PDL1 which switches off the body’s immune response.

Foot soldiers in rows

White blood cells, at times referred to as the foot soldiers of the immune system, come in many shapes. To survey these cells quickly, scientists from Australia’s RMIT and Harvard University in the US developed a “microlens” microscope, containing more than 10,000 small lenses which each scan a small section of a sample.

This image contains snapshots of thousands of white blood cells – each a 20th the width of a human hair – analysed for shape and ordered from most round (top) to least (bottom).

Immune cells defend the brain

This image shows the brain surface of a grey short-tailed opossum, which scientists at Australia’s Monash University use to study immune cells and blood vessels in marsupial brains and eyes. In green we see blood vessels and immune cells called macrophages from the pia mater – a delicate layer of cells which encases and nourishes the brain. Beneath lie densely packed brain cells called astrocytes (red) lining the surface of the cerebral cortex, or grey matter of the brain.

The Snapshots of the Immune System photography exhibition was held at St Ali Coffee Roasters in South Melbourne and will be displayed around Australia.