The present invention relates to a nucleic acid of the general formula (I): GlXmGn, which may be modified by a lipid. The invention relates further to a pharmaceutical composition containing an immune-stimulating agent according to the invention in combination with a pharmaceutically active carrier/vehicle (and, optionally, further auxiliary substances, additives and/or further adjuvants). The present invention can relate to a vaccine, which corresponds to a pharmaceutical composition of the invention, wherein the pharmaceutically active component induces a specific immune response (e.g. an antigen). The present invention can relate to the use of a nucleic acid of the invention or a pharmaceutical composition according to the invention for the treatment of infectious diseases, autoimmune disease, allergies or cancer diseases.