Enhanced immunogenicity and cross-reactivity of retro-inverso peptidomimetics of the major antigenic site of foot-and-mouth disease virus.

Retro-inverso analogues of peptides corresponding to the major antigenic site 141-159 of VP1 from two foot-and-mouth disease virus variants have been synthesized and tested for their antigenic and immunogenic properties. Antibodies to the L- and retro-inverso peptides were produced by injecting rabbits with peptides covalently coupled to small unilamellar liposomes containing monophosphoryl lipid A as adjuvant. When compared to the antibody response raised against the L-peptides, the duration of the IgG response that was induced by the retro-inverso peptides was significantly longer and the titer of anti-peptide antisera was much higher. Antibodies to retro-inverso peptides cross-reacted equally well with the respective parent L-peptides. These results, obtained with a viral sequence which was found previously to represent a good candidate for possible vaccination, show that retro-inverso peptidomimetics could be useful for enhancing the immunogenicity of peptides.