The present invention provides an immunostimulatory complex specifically adapted to act as adjuvant and as a peptide immunogen stabilizer. The immunostimulatory complex comprises a CpG oligonucleotide and a biologically active peptide immunogen. The immunostimulatory complex is particulate and can efficiently present peptide immunogens to the cells of the immune system to produce an immune response. The immunostimulatory complex may be formulated as a suspension for parenteral administration. The immunostimulatory complex may also be formulated in the form of w/o-emulsions or in-situ gelling polymers for the efficient delivery of immunogens to the cells of the immune system of a subject following parenteral administration, to produce an immune response.