The Adjuvant Effects of Amphipathic Helical Peptides

Subunit vaccines are the focus of research in developing new vaccines against infectious diseases. Due to the low immunogenicity of recombinant proteins, adjuvants are required for the activation of humoral and cellular immunity against a protein antigen. In this study, we reported the identification of a novel pathway that can activate humoral immunity against a recombinant protein without inducing inflammatory responses. By fusing an amphipathic helical peptide to GFP, one can increases the immunogenicity of GFP by up to 1000 fold. This enhancement was correlated with the ability of amphipathic helical peptides to bind to cell membranes and cause lysosomal membrane permeabilization. We showed evidence that the amphipathic helical peptide may induce the delivery of antigen across the lysosomal membrane into cytosol. Amphipathic helical peptide fusion provided a new pathway for stimulating immune responses against recombinant proteins.