T-helper 2 cells, also known as Th2 cells, are a type of immune cell that play a crucial role in the body's defense against infections, particularly those caused by parasites and allergens. They are part of the adaptive immune system and help activate other immune cells, such as B cells, which produce antibodies. These cells are characterized by their production of specific signaling molecules called cytokines, including IL-4, IL-5, and IL-13. These cytokines promote the growth and differentiation of B cells and enhance the activity of eosinophils and mast cells, which are important for combating parasitic infections and mediating allergic responses.