Porcine Circovirus Type 2 Vaccines: Commercial Application and Research Advances

Abstract

Porcine circovirus type 2 (PCV2) infection can lead to porcine circovirus-associated disease (PCVAD), causing great economic losses to the global swine industry. Conventional vaccination programs are a major measure in the prevention and control of this disease. Currently, there are 5 commercially available PCV2 vaccines in the international market and 10 kinds commercially available PCV2 vaccines in the Chinese market that confer good efficacy against this virus by alleviating clinicopathological manifestations and enhancing growth performance in pigs. In addition, diverse experimental PCV2 vaccines with protective efficiency have been developed, including attenuated chimeric, nucleic acid, subunit, multivalent, and viral-vectored vaccines. These experimental vaccines have been shown to be relatively effective in improving the efficiency of pig production and simplifying prevention procedures. Adjuvants can be used to promote vaccines with higher protective immunity. Herein, we review the application of multiple commercial vaccines over the years and research advances in experimental vaccines, which provide the possibility for the development of superior vaccines to successfully prevent and control PCV2 infection in the future.

The ultrasonically treated nanoliposomes containing PCV2 DNA vaccine expressing gC1qR binding site mutant Cap is efficient in mice

“…The pathogenesis of PCV2 is mainly attributed to the fact that PCV2 primarily attacks the host’s immune cells to suppress the immune system of infected piglets, leading to secondary or concurrent infection with multiple pathogens ( Hansen et al, 2010 ; Sahoo et al, 2022 ). Since the commercial vaccines come into the market in 2006, the PCV2-induced clinical signs are effectively reduced, and pork production is improved ( Guo et al, 2022 ). But for more than a decade, PCV2 has still been an epidemic in the pig herds of the world’s major pig-raising countries.…”

“…On the other hand, the smallest single-strand circular DNA genome of PCV2 makes the highest variation of PCV2 genotypes ( Lefebvre et al, 2009 ; Hou et al, 2019 ; Yuan et al, 2022 ). Although the commercial PCV2 vaccines have been proven to remain effective in protecting pigs against the most spread PCV2a, PCV2b, and PCV2d strains, the emerging new PCV2 strains may break through vaccine protection ( Guo et al, 2022 ). Thus, a vaccine platform that can be fast and easily operated is important to chase the evolutionary PCV2 strains.…”

Trained immunity is not universal: oral heat-inactivated Mycobacterium bovis confers no protection against the non-enveloped Porcine Circovirus 2

“…Porcine circovirus 2 (PCV-2), a small non-enveloped virus, is considered one of the most relevant pathogens that affect swine worldwide, mainly due to the substantial economic losses it causes to the pig industry [41]. PCV-2 infection has been associated with various disease syndromes in both domestic pigs and wild boar, such as PCV-2-systemic disease (PCV-2-SD, formerly known as postweaning multisystemic wasting syndrome), PCV-2-reproductive disease, PCV-2-subclinical infection and porcine dermatitis and nephropathy syndrome (PDNS).…”

“…PCV-2 infection has been associated with various disease syndromes in both domestic pigs and wild boar, such as PCV-2-systemic disease (PCV-2-SD, formerly known as postweaning multisystemic wasting syndrome), PCV-2-reproductive disease, PCV-2-subclinical infection and porcine dermatitis and nephropathy syndrome (PDNS). Importantly, PCV-2-SD affected pigs suffer from immunosuppression [41][42][43][44]. Currently, all commercialized PCV-2 vaccines are only indicated for the parenteral route [41], which is a limitation to target wild boar and free-range pigs [45,46].…”

“…Importantly, PCV-2-SD affected pigs suffer from immunosuppression [41][42][43][44]. Currently, all commercialized PCV-2 vaccines are only indicated for the parenteral route [41], which is a limitation to target wild boar and free-range pigs [45,46]. Consequently, although several attempts to develop oral vaccines composed of recombinant bacteria [47,48] or yeasts [49][50][51][52] expressing PCV-2 Cap protein have revealed promising results, there is still a long way to go before achieving an orally delivered preparation that is feasible to protect swine against PCV-2.…”