Purification of Classical Swine Fever Virus E2 Subunit Vaccines Based on High Affinity Peptide Ligand

The purification of expressed proteins is the most critical part of subunit-- vaccine production. Protein-purification methods such as affinity chromatography and ion exchange still have the shortcomings of being time consuming and complicated. With the rapid development of computational molecular-simulation technology, structure-based peptide-ligand design has become feasible. Objection: We aimed to apply molecular docking for a peptide ligand designed for classical swine fever virus (CSFV) E2 purification.

Computational-derived peptides were synthesized, and the in vitro binding interaction with E2 was investigated. The effects of purification on E2 were also evaluated.

The best peptide recognizing E2 was P₆, which had a sequence of KKFYWRYWEH. Based on kinetic surface plasmon resonance (SPR) analysis, the apparent affinity constant of P6 was found to be 148 nM. Importantly, P₆ showed suitable binding affinity and specificity for E2 purification from transgenic rice seeds. Evaluation of immune antibodies in mice showed that the antibody- blocking rate on day 42 after inoculation reached 86.18% and 90.68%.

The computational-designed peptide in this study has high sensitivity and selectivity and is thus useful for the purification of CSFV E2. The novel method of design provided a broad platform and powerful tool for protein-peptide screening, as well as new insights into CSFV vaccine design.