Reduction of Postweaning Multisystemic Wasting Syndrome-Associated Clinical Symptoms by Virus-Like Particle Vaccine Against Porcine Parvovirus and Porcine Circovirus Type 2

Abstract

The porcine circovirus type 2 (PCV2) capsid (Cap) protein and porcine parvovirus (PPV) VP2 protein have been studied in vaccines to control postweaning multisystemic wasting syndrome (PMWS). Virus-like particle (VLP) vaccines are nonreplicative vectors that deliver epitopes and induce immune responses. However, most VLP vaccines are recombinant proteins expressed in eukaryotic systems and are expensive and complex. In this study, the full-length PCV2-Cap and PPV-VP2 proteins were expressed in Escherichia coli, which selfassembled into VLPs. The highly soluble proteins were purified using Ni-chelating affinity chromatography. The proteins self-assembled into VLPs of *20 nm (Cap VLP) and 25 nm (VP2 VLP) in diameter. The immunogenicities of Cap VLP and VP2 VLP were determined in piglets coinfected with PPV and PCV2 postimmunization. The results suggested that Cap VLP and VP2 VLP did not antagonize each other. The combined vaccine induced stronger humoral and cellular immune responses and provided the best protection against PPV and PCV2 coinfection. On a farm containing PMWS-infected pigs, the combined Cap VLP and VP2 VLP vaccine significantly improved piglet growth indices; the average daily weight gains were significantly higher than those of the Cap VLP vaccine and nonimmunized groups. Thus, Cap and VP2 protein expression in E. coli is feasible for large-scale VLP vaccine production. The combined vaccine may be a promising candidate vaccine for better preventing PMWS-associated diseases coinfected with PCV2 and PPV.

Virus-Like Particles: Revolutionary Platforms for Developing Vaccines Against Emerging Infectious Diseases

“…Similarly, in a recent study, the full-length CP of type 2 porcine circovirus and VP2 protein of porcine parvovirus were expressed in E. coli , which were self-assembled into VLPs. The study suggested that the expression of the CP and VP2 in E. coli is possible for the mass development of VLP vaccines ( Liu et al, 2020 ). Yazdani et al (2019) investigated the possibility of utilizing VLPs of grapevine fanleaf virus (GFLV) as a potential vector for presenting the L2 epitope of HPV.…”

A Comprehensive Review of Our Understanding and Challenges of Viral Vaccines against Swine Pathogens

“…While most vaccines target only one virus at a time, multivalent vaccines use two or more viruses. The most common pathogens often targeted together include PCV2 with other viral and non-viral pathogens [ 159 , 160 , 161 , 162 , 163 ]. VLPs produced by the Cap protein of PCV2 are remarkably efficient against its infection.…”

Porcine Circovirus Type 2 Vaccines: Commercial Application and Research Advances

“…zooepidemicus (SEZ) were inserted into the swine pox virus (SPV) genome to construct the recombinant swinepox virus rSPV-ICS, in which the rSPV-ICS conferred good protection against co-challenge of PCV2 and SEZ [69]. The combined vaccine based on porcine PCV2 Cap VLP and porcine parvovirus (PPV) VP2 VLP significantly improved the growth performances of piglets and could alleviate PCVAD and related diseases caused by PCV2 and PPV co-infection [70]. A recombinant BacSC-Dual-GP5-Cap vaccine, which simultaneously expressed PRRSV GP5 glycoprotein and PCV2 capsid protein in the baculovirus system, can elicit considerable levels of virus neutralization titers and induce lymphocyte proliferation responses [71].…”