IL-4 (Interleukin-4)

Interleukin-4 (IL-4) is a signaling molecule, or cytokine, produced mainly by certain immune cells. It plays a key role in coordinating the immune response by promoting the development of specific immune cells called Th2 cells, which help defend against parasites and are involved in allergic reactions. IL-4 also encourages B cells to produce antibodies, particularly IgE, which are important in allergies. Overall, IL-4 helps regulate immune system activity, balancing defenses against infections while also contributing to allergic and hypersensitivity reactions.