Proc. Natl Acad. Sci. USA 107, 622–627 (2010)

Synthetic peptides, which are useful as antigens for the production of well-defined antibodies for vaccines, are themselves not reactive and require a substance (known as an adjuvant) to evoke an immune response. Because adjuvants such as oil emulsions and other biological materials are heterogeneous and poorly defined, characterizing and understanding their mechanisms is a challenge. Researchers at the University of Chicago and Illinois Institute of Technology have now shown that a self-assembling peptide can act as an immune adjuvant.

Joel Collier and colleagues attached a short ovalbumin peptide obtained from a chicken egg to a short fibril-forming peptide, and allowed the construct to self-assemble into micron-long fibrils that are soluble in water. The fibrils containing the ovalbumin antigen evoked an immune response in mice, whereas fibrils without the antigen did not. The response was similar to when ovalbumin peptide alone was administered with a conventional adjuvant, suggesting that the self-assembled fibrils can act as an adjuvant. Experiments with unconjugated mixtures of the ovalbumin and fibril-forming peptides completely abolished the immune response, further suggesting that covalent coupling between the peptides and self-assembly are important.

Although the mechanisms remain unclear, and definitive long-term studies need to be carried out, self-assembling peptides represent a simple way to enhance antibody responses towards antigenic peptides.