<unk> s are a subset of cytokines that are produced by a type of immune cell known as a lymphocyte. They are protein mediators typically produced by T cells to direct the immune system response by signaling between its cells.<unk> s have many roles, including the attraction of other immune cells, including macrophages and other lymphocytes, to an infected site and their subsequent activation to prepare them to mount an immune response. Circulating lymphocytes can detect a very small concentration of<unk>  and then move up the concentration gradient towards where the immune response is required.<unk> s aid B cells to produce antibodies. Important<unk> s secreted by the T helper cell include: * Interleukin 2 * Interleukin 3 * Interleukin 4 * Interleukin 5 * Interleukin 6 * Granulocyte-macrophage colony-stimulating factor * Interferon-gamma
Lymphokine
Cytokine
Hormone
Neurohormone
Inflammatory cytokine
Gastrointestinal hormone
Xenohormone
Local hormone