Candidate Vaccine Focused on a Classical Swine Fever Virus Epitope Induced Antibodies with Neutralizing Activity

Classical swine fever is a highly contagious viral disease for which many researchers are endeavoring to develop safe and efficient vaccines. An amino acid sequence, TAVSPTTLR, residing in glycoprotein E2, was identified as a highly conserved neutralizing epitope. This epitope was demonstrated to have the capacity of inducing neutralizing antibodies, and the sequences flanking it may contribute to the production of functional humoral immune responses. One interesting question is whether such a structural contribution can be compensated for. In this report, we designed and produced several chimeric recombinant proteins comprising 2, 4, or 6 repeats of this epitope fused to the C-terminus of the GST protein. These proteins were investigated for their capacity of inducing antibodies with neutralizing activity. The results showed that the 6-repeated chimeric recombinant protein managed to elicit epitope-specific neutralizing antibodies, while the 2- or 4-repeated recombinant proteins did not produce such antibodies in significant amounts if any.