Abstract: The present invention relates to vaccine compositions based on Gram-negative outer membrane vesicles displaying antigens of pathogens expressed as part of a fusion protein comprising N-terminal parts of surface expressed lipoproteins of Gram-negative bacteria, and use of such compositions in vaccination. The invention further relates to the fusion lipoproteins comprising N-terminal parts of surface expressed lipoproteins of Gram-negative bacteria and antigens of pathogens fused thereto, DNA constructs and bacterial host cells for expressing these fusion lipoproteins and to methods for producing outer membrane vesicles displaying the fusion lipoproteins.