The present invention provide a compound represented by the following formula (1)wherein each symbol is as defined in the specification, or a salt thereof.The compound of the present invention and a salt thereof can preferentially induce production of IL-4, which is one kind of cytokines that control action of immunocytes. Therefore, it is useful for the prophylaxis or treatment of autoimmune diseases, infectious diseases and the like, and prophylaxis or treatment of diseases caused by functional promotion of Th1 cells.
