LA JOLLA—Your immune system comes ready for battle against bacteria, viruses, fungi and even cancer. But in cases of autoimmune disease, the immune system’s superpowers turn it into a supervillain. Now, Salk Institute scientists have discovered a way to stop certain immune system cells from mistakenly attacking the body. Their findings, published the week of August 26, 2019, in the journal Proceedings of the National Academy of Sciences, suggest a new way to target Th17 helper T cells, a type of immune cell that produces interleukin 17, a molecule known to be at the root of autoimmune diseases such as multiple sclerosis, rheumatoid arthritis and psoriasis. Previous efforts targeting Th17 helper T cells have had limited success.