Abstract: The present invention relates to vaccine compositions, most notably vaccine compositions wherein the antigenic component is large, for example over 50 kDa, or multimeric, i.e. comprised of subunits. Such antigenic components are of particular interest, because they may represent antigenic components from pathogens that currently it is not possible to vaccinate against. The invention relates to a composition comprising a particle displaying an antigenic component, wherein said composition comprises an antigenic component comprising a first peptide tag, and a moiety comprising a second peptide tag, wherein the antigenic component and the moiety are linked via an isopeptide bond between said first and second peptide tags, and wherein the antigenic component is over 50 kDa, or alternatively is multimeric.