Abstract: A bifunctional composition comprising an intracellularly effective immunomodulating nucleic acid component containing at least one immunostimulatory, immunoinhibitory or immunomodulating motif and selected from a mononucleotide, a dinucleotide, an oligonucleotide or a polynucleotide with either a natural phosphodiester backbone or a modified backbone, optionally in combination with a specific antigen, in association with a protein binding to specific receptors on mammalian cell surfaces selected from the group consisting of cholera toxin (CT), the subunit B of CT (CTB), Escherichia coli heat labile enterotoxin (LT), the subunit B of LT (LTB), and proteins or protein derivatives that react with antiserum to CT or LT, bind to GM1 ganglioside, ADP-ribosylates an acceptor protein, or give rise to accumulation of cyclic AMP in target cells, and antibodies or other proteins which after binding to a specific cell surface component can be internalized into the cell, is described.