Cytokines are small secreted proteins released by cells that have a specific effect on the interactions and communications between cells. The word cytokine is derived from the Greek kytos meaning "hollow" or "vessel", while kinein means "to move". It was originally used to separate a group of immuno-regulatory proteins, such as interleukins, from other chemicals, known as growth factors, that modulated the proliferation and bioactivation of nonimmune cells. Cytokines aid cell to cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection and trauma.This is a page.