A wide array of cells and proteins influences every immune response to a pathogen. Some get the defense into gear by causing inflammation. Others put the brakes on the response after the foe is defeated and return the body to normal.
In rheumatoid arthritis–as in other autoimmune diseases–the immune system remains revved up and damages healthy tissues. Scientists now report that a signaling molecule called vasointestinal peptide, or VIP, can restore order to the immune system in arthritic mice and even reverse arthritis.
While tests of VIP on people are still years away, the compound is attracting attention. In mice, it seems to alter the activities of some immune cells and the amounts of some proteins released into synovial fluid, the viscous liquid that lubricates joints. In so doing, VIP reduces inflammation, cartilage damage, and bone erosion in the animals, the researchers report in the May Nature Medicine.