New Rules Of The Immune System

Regulatory T cells

Most white blood cells attack infections in the body by triggering an immune response. Regulatory T cells act like a team of healers responsible for stopping the attacking cells once they have done their job, repairing the collateral damage caused to tissues and organs, and promoting healing. 

These regulatory T cells shut down inflammation while repairing damage caused by our immune system responses to injury or illness. Experiments in mice with a drug developed by the team showed that these T cells can be attracted to specific body parts, increased in numbers, and activated to suppress the immune system to rebuild tissues. 

Site-specific

Currently, anti-inflammatory drugs treat the entire body rather than just the specific part requiring treatment, making the patient more vulnerable to infection. Findings from this study suggest that it may be possible to temporarily shut down the body’s immune response and repair damage in any part of the body without affecting the rest of the body. Meaning that higher and more targeted doses of medication could be used to treat diseases with potentially rapid results. 

"We've uncovered new rules of the immune system. This 'unified healer army' can do everything -- repair injured muscle, make your fat cells respond better to insulin, regrow hair follicles. To think that we could use it in such an enormous range of diseases is fantastic: it's got the potential to be used for almost everything," said Professor Adrian Liston in the University of Cambridge's Department of Pathology, senior author of the paper.

"It's difficult to think of a disease, injury, or infection that doesn't involve some kind of immune response, and our finding really changes the way we could control this response," added Liston. "Now that we know these regulatory T cells are present everywhere in the body, in principle we can start to make immune suppression and tissue regeneration treatments that are targeted against a single organ -- a vast improvement on current treatments that are like hitting the body with a sledgehammer."

Early testing

For this study, the team analyzed the regulatory T cells present within 48 different tissues of the body of mice. This analysis revealed that these cells were not specialized or static, rather they moved throughout the body to where they were needed. Using a drug they developed, they demonstrated that it is possible to attract these cells to a specific part of the body, increase their numbers, and activate the cells to turn off the body’s immune responses to just that one organ or tissue to promote healing there. 

"By boosting the number of regulatory T cells in targeted areas of the body, we can help the body do a better job of repairing itself or managing immune responses," said Liston. "There are so many different diseases where we'd like to shut down an immune response and start a repair response, for example, autoimmune diseases like multiple sclerosis, and even many infectious diseases."

What this means

The discovery of these new rules of the immune system could help to improve the treatment of many inflammatory diseases. 

Most symptoms of infection are not from the virus itself; they are from the body’s immune system responses attacking the virus. When the virus has passed peak the regulatory T cells typically switch off the immune responses. However, in some people, this process is not very efficient, and it can result in ongoing issues. These new findings show the potential of using a drug to shut down immune responses in a specific area to promote healing while at the same time letting the immune system in the rest of the body continue to function normally. 

This may also be beneficial for those receiving organ transplants who must take immuno-suppressant drugs for the rest of their lives to prevent organ rejection due to the body sending a severe immune response against the transplanted organ. This process also makes the patient highly vulnerable to infections. These findings could help to design a new drug to shut down the immune responses against the transplanted organ while allowing the rest of the body to work normally and enable the patient to lead a more normal life.