Scientists have discovered a novel type of cell in mice which suppresses the immune system, protecting the animal's own cells from immune system attack.
The discovery has been made by researchers at the Dana-Farber Cancer Institute in Boston.
This "suppressor" cell reduces the production of harmful antibodies that can drive lupus and other autoimmune diseases in which the immune system mistakenly turns on otherwise healthy organs and tissues.
Now the discovery will be used to explore therapies that might control the hyperactive immune system in lupus.
"These CD8+ T suppressor cells represent a potential new lever for lowering the strength of the immune response in autoimmune diseases such as lupus," said Harvey Cantor.
Until now, scientists searching for cells involved in quieting the immune system response had focused their hunt on "regulatory CD4+ T cells"-also known as CD4+ Treg.
Cantor and his team reported that not just CD4+T cells but CD8+ T cells as well include a subset that helps dampen the immune response. Instead of reducing inflammation like their CD4 cousins, the CD8+ T regulatory cells ensure that the immune system doesn't produce antibodies that attack normal cells.
Lead author Hye-Jung Kim and colleagues made the discovery as they were winding up unrelated LRI-funded work into the role in autoimmunity of a protein found inside immune cells called osteopontin.
"Our LRI funds allowed us to carry out the early experiments that led to the definition of the CD8 suppressor cells.
"We were testing osteopontin's activity against a population of cells known as follicular T helper cells.
"We noted that the cells were responsive to osteopontin but also that they expressed what we knew to be the target of suppressor CD8+ T cells," said Cantor.
The findings were published in the Nature.