These are cell-derived chemicals that are secreted by various types of cells and act on other cells to stimulate or inhibit their function. Chemicals derived from lymphocytes are called “lymphokines.” Chemicals derived from lymphocytes that act on other white blood cells are called “interleukins,” that is, they interact between two types of leukocytes.
Interleukins are a group of cytokines that are expressed by white blood cells (leukocytes, hence the -leukin) as a means of communication (inter-). A list of interleukins with function:
IL-1: (secreted by macrophages), induces acute phase reaction
IL-2: (secreted by T cells) stimulates growth and differentiation of T cell response.
IL-3: (secreted by T cells), stimulates bone marrow stem cells.
IL-4: involved in proliferation of B cells, and the development of T cells and mast cells. Role in allergic responses.
IL-5: role in stimulation of B cells, eosinophil production, IgA production
IL-6: (secreted by macrophages) induces acute phase reaction
IL-7: involved in B, T and NK cell survival, development and homeostasis
IL-8: Neutrophil chemotaxis
IL-9: stimulates mast cells
IL-10: inhibits Th1 cytokine production
IL-11: acute phase protein production
IL-12: NK cell stimulation, Th1 cells induction
IL-13: Stimulates growth and differentiation of B-Cells, inhibits Th1 cells and the production of macrophage inflammatorycytokines
IL-17: Induces production of inflammatorycytokines
IL-18: Induces production of Interferon-Gamma (IFNy)