The present invention is related to the fields of molecular biology, virology, immunology and medicine. The invention provides a modified virus-like particle (VLP) comprising a VLP which can be loaded with immunostimulatory substances, in particular with DNA oligonucleotides containing non-methylated C and G (CpGs), and particular HIV peptides linked thereto. Such CpG-VLPs are dramatically more immunogenic that their CpG-free counterparts and induce enhanced B and T cell responses. The immune response against HIV peptides optionally coupled, fused or attached otherwise to the VLPs is similarly enhanced as the immune response against HIV peptides are especially directed to the Th1 type. Antigens attached to CpG-loaded VLPs may therefore be ideal vaccines for prophylactic or therapeutic vaccination against allergies, tumors and other self-molecules and chronic viral diseases.