New discoveries about regulatory T cells could help treat diseases like multiple sclerosis

Scientists have discovered that regulatory T cells, a type of white blood cell, constantly travel throughout the body seeking out and repairing damaged tissue.

Regulatory T cells were believed to exist as multiple populations restricted to specific parts of the body.

Now, researchers have found that they travel through the body as a large population of cells and target areas of inflammation, causing nerve damage and loss of mobility.

Researchers at the University of Cambridge say this discovery of “new rules of the immune system” could improve treatments for inflammatory diseases such as multiple sclerosis (MS).

“We have discovered new rules of the immune system. This 'unified healing army' can do everything from repairing injured muscle, making your fat cells respond better to insulin, and regrow hair follicles,” study author Adrian Liston, a professor at the Department of Pathology at the University of Cambridge, said in a report.Press release,

“It's amazing to think that we could use it to treat such a huge number of diseases: it has the potential to be used for almost everything,” he said.

'Unified Healing Force'

Effector T cells such as cytotoxic and helper T cells are known to fight infections by activating the immune response by directly and indirectly attacking viruses and bacteria.

Most symptoms of infections like COVID-19 are caused not by the virus itself, but by the body's immune system attacking the virus.

Once the virus reaches its peak, regulatory T cells should shut down the immune response.

“They initiate a healing response, which makes them a very powerful cell type to fight any inflammatory condition or any autoimmune disease,” Liston said.

But in some people the procedure may be ineffective, leading to long-term problems.

This new discovery may make it possible to use a drug to specifically switch off an immune response, for example, in the lungs, allowing the immune system in the rest of the body to continue working normally.

Current treatments are like 'hitting the body with a hammer'

Researchers say most anti-inflammatory drugs, taken as oral pills or injections, are delivered throughout the body, when treatment is typically needed only for one organ.

They hope their discovery will change that, with higher, more targeted doses of drugs and more rapid results.

“Now that we know these regulatory T cells are everywhere in the body, in theory we can start creating immune suppression and tissue regeneration treatments that target a single organ — a huge improvement over current treatments that are like hitting the body with a hammer,” Liston said.

However, at baseline, tissues have very low numbers of these regulatory T cells that help to prevent, repair, and initiate healing. So they don't always calm inflammation effectively.

“We're really lucky that regulatory T cells are a renewable resource. They're made in an organ called the thymus that's located right above our heart, and they can continuously produce these cells throughout our lives,” Liston said.

The source of these cells, the thymus, gets smaller when people are stressed, sick or pregnant, Liston says. It also gets smaller as we age.

“There is a limit to it, but these cells will continue to be generated throughout our lives,” Liston said.

Now, the research team says they are trying to enhance these properties in patients with inflammatory conditions in any of their organs.

The team believes the viral vector could be used to inject DNA, creating a potent drug that could boost the population of regulatory T cells.

In the case of MS, where the immune system mistakenly attacks the protective covering of the nerves, this injection will go to the brain.

“In multiple sclerosis, there's an inflammatory process going on inside the brain that damages the central nervous system and disrupts signaling from the brain to the muscles. This is all coordinated by the immune system,” Liston said.

“If you send regulatory T cells into the brain, they can turn off inflammation and they can also start a healing response,” Liston said.

So far, the studies published in the journal Immunity have been conducted only on animal models such as mice.

The researchers analyzed regulatory T cells in 48 different tissues of mice and, using a drug they developed, successfully transferred regulatory T cells to a specific part of the body, activating them to turn off the immune response and promote healing in only one organ or tissue.

Several more safety studies will be needed before the drug can be proposed for testing in humans.

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