A Japanese research group has said that it became the world's first to succeed in producing regulatory T cells, which suppress excessive immune responses, from human induced pluripotent stem (iPS) cells.

The team, including Kyoto University researchers, expects that the production method, if put into practical use, will make it possible to mass produce the cells, known for their effectiveness in suppressing rejection in transplantation medicine.

The study was published in the U.S. journal Cell Stem Cell on Friday.

The current standard treatment for autoimmune diseases, stemming from overactive immune cells in the body, heavily relies on immunosuppressive drugs. Treatment using regulatory T cells is attracting attention, but it is difficult to produce the cells in vitro in amounts large enough for therapeutic use.

The research group cultured T cells, a type of immune cell, that were produced from human iPS cells, employing a combination of four reagents known to encourage T cells to develop into the regulatory type.

The cells produced from iPS cells were mixed with aggressive T cells, which attack cancer, and were cultured further. The team then obtained cells with immunosuppressive effects similar to those of the regulatory T cells.

In addition, when immune-controlling T cells made from iPS cells were transplanted into mice with graft-versus-host disease, in which immune cells attack their own organs, the immune responses of the mice were suppressed and their survival periods became longer.

"If we use iPS cells, we'll be able to secure large amounts of cells quickly, which will lead to the development of drugs to treat autoimmune diseases," said team member Shin Kaneko, a professor at Kyoto University's Center for iPS Cell Research and Application.