In general, immune cells are pretty super.
They help protect your body from all kinds of invaders, including viruses and bacteria.
However, researchers from Scripps University have found an immune cell that takes protection to the next level — in a “Supermanish” sort of way.
This previously unknown immune cell resembles a conventional T cell. However, it can transform into a regulatory T cell (Treg).
Regulatory T cells have the ability to control the severity of the body’s immune response and protect the body from autoimmune diseases like type 1 diabetes and rheumatoid arthritis.
Autoimmune diseases occur when the immune system mistakenly attacks the body’s own cells. Understanding how regulatory T cells are activated could lead to new treatments.
The findings of the new study were published online today in the journal Proceedings of the National Academy of Sciences.
Starting with a Single Cell
In the new study, Scripps researchers started by isolating a single regulatory T cell from the spleen of a mouse.
This mouse had been genetically engineered to be prone to developing type 1 diabetes, which is what’s known as a mouse model for the disease.
The nucleus of this cell containing the genetic material was inserted into a mouse egg that had its own nucleus removed.
This cloning method called Somatic Cell Nuclear Transfer (SCNT) was used to create Dolly the sheep.
Although this method is expensive, “the new models that are generated through SCNT are a perfect genetic copy of the original cell. You can’t beat this accuracy,” Dr. Oktay Kirak, Ph.D., a biologist at The Scripps Research Institute, told Healthline in an email.
As a clone, the new mouse can make only one type of regulatory T cell. It’s the same as the one taken from the original mouse.
The researchers discovered that the new mouse’s Treg developed in the thymus, an organ that is part of the immune system. This made it a “naturally” occurring regulatory T cell, or nTreg.
These are distinct from those that develop outside of the thymus, which are called peripherally-induced Tregs or pTregs.
Clark Kent and Superman Cells
Even though the new mouse could only make one type of T cell, the researchers soon spotted a second type in the mouse’s thymus and spleen.
This turned out to be a precursor for the nTreg, or a pre-nTreg. Although these cells appeared to be different, they were genetically identical.
The different appearance of the cells was the result of a gene called FoxP3. This gene was inactive in the precursor cell. But the gene could be switched on, transforming the cell into an nTreg.
Kirak compares these two cells to Clark Kent (pre-nTreg) and Superman (nTreg).
“In our analogy, conventional T cells would be all other humans that are not superheroes,” said Kirak.
Many scientists have thought that conventional T cells were pretty much the same. This study, though, showed that cells that look “conventional” might actually be much more.
“There are subsets within this pool of conventional T cells with very different potentials,” said Kirak. “Clark Kent appears like any other ordinary human, but he is very different than other humans.”
Scientists don’t know exactly how many subsets of T cells there are. More work is needed to understand this and to figure how to turn the information into new treatments.
Drugs Might Ramp up Regulatory T Cells
Understanding how pre-nTregs become full-fledged nTregs might lead to the development of new drugs to fight autoimmune diseases.
The types of nTregs studied by the Scripps researchers are known to be present in patients with type 1 diabetes. For some reason, though, this is not enough to prevent an autoimmune attack on the cells of the pancreas.
“Whatever they are doing there, it is not sufficient to stop the autoimmune attack,” said Kirak. “New [mouse] models can provide new insights into diseases and have the potential to provide new therapeutics.”
Other researchers are already investigating how to alter the body’s immune response with regulatory T cells.
One study last year looked at repairing or replacing Tregs with immunotherapy in people with type 1 diabetes.
Some researchers hope to use regulatory T cells to prevent the immune system from attacking transplanted organs. This process would be similar to turning down the immune response against cells you would like to be your own.
There is also the potential for new cancer treatments. In cancer, regulatory T cells can block the immune system from attacking tumor cells, which look like the body’s own cells.
Exactly how regulatory T cells function in cancer is unknown.
“We don’t know whether nTregs or pTregs are recruited into tumors,” said Kirak, “and what kind of function they execute within the tumor to protect the tumor from an antitumor immune attack.”
The researchers plan to develop ways to “unmistakably identify these novel T cell subpopulations.” They would also like to extend their cloning method to investigate the body’s immune response to cancer.