A composition for stimulating NKT cells to produce anti-cancer and anti-viral cytokines without causing anergy of NKT cells includes a glycolipid antigen and a nanoparticle conjugated with the glycolipid antigen. The glycolipid antigen and the nanoparticle are not antigenic in mouse and human being. The composition can further include covalent or non-covalent connection between the glycolipid antigen and the nanoparticle. The glycolipid antigen is alpha-galactosylceramide or an analog of that. The nanoparticle can be a polymer. A production method of the composition includes preparing a nanoparticle and a glycolipid antigen and loading the glycolipid antigen to the nanoparticle. The glycolipid antigen can be coated onto the surface of the nanoparticle or encapsulated within the nanoparticle. A method of stimulating NKT cells to produce anti-cancer and anti-viral cytokines without causing anergy of NKT cells is also provided.
