Preliminary Evaluation of a Candidate Multi-Epitope-Vaccine Against the Classical Swine Fever Virus

A multi-epitope-vaccine MEV^ABC consisting of two linear neutralizing determinants (BC1: aa693-716; A6: aa844-865) located on antigenic unit B/C and unit A of glycoprotein E2 was prepared to evaluate whether a combination strategy is effective in the design of peptide vaccines. After immunization, pig sera collected every one to two weeks were evaluated by enzyme linked immunosorbent assay. C-strain-induced anti-sera and hyper-immune sera cannot recognize overlapping peptides that cover the E2 N-terminus, while MEV^ABC is able to elicit high levels of peptide-specific antibody response. When compared with previously studied peptide vaccines PV-BC1 and PV-A6, the same dose of either component in the MEV^ABC increases the BC1- or A6-specific antibodies (to 1/3-1/2 of the levels of the separate vaccines). However, the synergy between the antibodies may make MEV^ABC much more potent. Moreover, anti-C-strain immunity pre-existing in pigs does not disturb the sequent MEV^ABC vaccination. Thus, MEV^ABC can be administrated to pigs which already possess anti-classical swine fever virus immunity. MEV^ABC is a promising candidate marker vaccine.