Effect of carrier on the immunogenic capacity of synthetic cholera vaccine

In the design of the synthetic antigens and synthetic vaccines, primary consideration should be given to the choice of the carrier. Since small peptides which are being used as the relevant antigenic determinants are likely to be poor immunogens as such, the augmentation of their immunogenic capacity by the carrier or any other means is crucial for the induction of immunity. In the present study, we explored several approaches for the enhancement of the immune response towards synthetic peptides derived from the B-subunit of cholera toxin. The results indicate that the use of tetanus toxoid as a macromolecular carrier, polymerization of the peptide without any external carrier and the conjugation of dipalmityl side chain had comparable effects in enhancing the immune response to several synthetic peptides. This effect was manifested both at the level of antibodies produced and in their capacity to neutralize the biological activity of the cholera toxin. Prior exposure to the carrier resulted in a dose-dependent suppression against the synthetic epitope attached to it.