Abstract: The present invention provides a method of selectively augmenting an immunosuppressive function in various functions of NKT cells, and a method of efficiently inducing an antigen specific immunosuppression in vivo, as well as a pharmaceutical obtained by applying the same. More particularly, the present invention provides a pharmaceutical (e.g., a preventive or therapeutic agent for immune diseases such as allergic disease and autoimmune disease) containing a CD1d ligand and a target antigen (e.g., allergen, autoantigen). Preferably, the pharmaceutical contains a drug delivery vehicle including the CD1d ligand and the target antigen and having a lumen.