T Helper 17 Cells, or Th17 cells, are a type of immune cell that play a crucial role in the body's defense against infections. They are a subset of T cells that produce specific signaling molecules called cytokines, particularly IL-17. This helps recruit other immune cells to sites of inflammation and infection, enhancing the body's ability to fight off pathogens. These cells are important in protecting against certain bacteria and fungi, but they can also contribute to autoimmune diseases when their activity is not properly regulated. Understanding Th17 cells is essential for developing therapies for conditions like multiple sclerosis and rheumatoid arthritis.