Development of a vaccine marker technology: Display of B cell epitopes on the surface of recombinant polyomavirus‐like pentamers and capsoids induces peptide‐specific antibodies in piglets after vaccination

Abstract

Highly immunogenic capsomers (pentamers) and virus-like particles (VLPs) were generated through insertion of foreign B cell epitopes into the surface-exposed loops of the VP1 protein of murine polyomavirus and via heterologous expression of the recombinant fusion proteins in E. coli. Usually, complex proteins like the keyhole limpet hemocyanin (KLH) act as standard carrier devices for the display of such immunogenic peptides after chemical linkage. Here, a comparative analysis revealed that antibody responses raised against the carrier entities, KLH or VP1 pentamers, did not significantly differ up to 18 weeks, demonstrating the highly immunogenic nature of VP1-based particulate structures. The carrier-specific antibody response was reproducibly detected in the meat juice after processing. More importantly, chimeric VP1 pentamers and VLPs carrying peptides of 12 and 14 amino acids in length, inserted into the BC2 loop, induced a strong and long-lasting humoral immune response against VP1 and the inserted foreign epitope. Remarkably, the epitope-specific antibody response was only moderately decreased when VP1 pentamers were used instead of VLPs. In conclusion, we identified polyomavirus VP1-based structures displaying surface-exposed immunodominant B cell epitopes as being an efficient carrier system for the induction of potent peptide-specific antibodies. The application of this approach in vaccine marker technology in livestock holding and the meat production chain is discussed.

Chimeric Porcine Circoviruses (PCV) Containing Amino Acid Epitope Tags in the C Terminus of the Capsid Gene Are Infectious and Elicit both Anti-Epitope Tag Antibodies and Anti-PCV Type 2 Neutralizing Antibodies in Pigs

“…Since PCV2 infection is mostly subclinical, it is important to design a new vaccine that can track the virus's spread and herd level immunity. Immunogenic epitopes have been expressed on surface-exposed domains of viral proteins in other viruses, resulting in specific immune responses (12,18,21,22,25). In part due to its small genome size, the ability of the PCV genome to tolerate insertion and display foreign epitopes has not been explored.…”

Bcr-Abl fusion sequences do not induce immune responses in mice when administered in mouse polyomavirus based virus-like particles

“…Furthermore, exploitation of MPyV-VLPs as carriers of foreign epitopes has been examined. Several types of chimeric VLPs were prepared and used in different immunization protocols (17)(18)(19). In some studies, the short epitopes were exposed on the surface of the particle by insertion into the surface loops of the major structural protein VP1.…”