Incidence of Carassius auratus Gibelio Gill Hemorrhagic Disease Caused by CyHV-2 Infection Can Be Reduced by Vaccination with Polyhedra Incorporating Antigens

Abstract

Encapsulation of antigens within protein microcrystals (polyhedra) is a promising approach for the stable delivery of vaccines. In this study, a vaccine was encapsulated into polyhedra against cyprinid herpesvirus II (CyHV-2). CyHV-2 typically infects gibel carp, Carassius auratus gibelio, causing gill hemorrhagic disease. The vaccine was constructed using a codon-optimized sequence, D4ORF, comprising the ORF72 (region 1–186 nt), ORF66 (region 993–1197 nt), ORF81 (region 603–783 nt), and ORF82 (region 85–186 nt) genes of CyHV-2. The H1-D4ORF and D4ORF-VP3 sequences were, respectively, obtained by fusing the H1-helix sequence (region 1–90 nt) ofBombyx mori cypovirus(BmCPV) polyhedrin to the 5′ terminal end of D4ORF and by fusing a partial sequence (1–279 nt) of the BmCPV VP3 gene to the 3′ terminal end of D4ORF. Furthermore, BmNPV-H1-D4ORF-polh and BmNPV-D4ORF-VP3-polh recombinant B. mori nucleopolyhedroviruses (BmNPVs), belonging to the family Baculoviridae, and co-expressing BmCPV polyhedrin and H1-D4ORF or D4ORF-VP3, were constructed. H1-D4ORF and D4ORF-VP3 fusion proteins were confirmed to be encapsulated into recombinant cytoplasmic polyhedra by Western blotting. Degradation of vaccine proteins was assessed by SDS-PAGE, and the results showed that the encapsulated vaccine proteins in polyhedra could be protected from degradation. Furthermore, when gibel carp were vaccinated with the purified polyhedra from BmNPV-H1-D4ORF-polh and BmNPV-D4ORF-VP3-polh via injection, the antibody titers in the serum of the vaccinated fish reached 1:6400–1:12,800 at 3 weeks post-vaccination. Therelative percentage of survival of immunized gibel carp reached 64.71% and 58.82%, respectively, following challenge with CyHV-2. These results suggest that incorporating vaccine protein into BmCPV polyhedra may be a novel approach for developing aquaculture microencapsulated vaccines.

Gut mucosal immune responses and protective efficacy of oral yeast Cyprinid herpesvirus 2 (CyHV-2) vaccine in Carassius auratus gibelio

“…Vaccination has been shown to be the most effective countermeasure against viral infection due to its immunostimulatory effect, thus reducing morbidity and mortality. Experimental studies on CyHV-2 vaccines began in 2013 (7), and several vaccines have since been developed and used to prevent and control CyHV-2 infection, including inactivated vaccines, live vaccines, DNA vaccines, and subunit vaccines (7)(8)(9)(10)(11)(12). Particularly, live vaccines are the closest alternative to natural pathogen infection, in addition to being powerful and eliciting durable immune responses (10).…”

“…Experimental studies on CyHV-2 vaccines began in 2013 (7), and several vaccines have since been developed and used to prevent and control CyHV-2 infection, including inactivated vaccines, live vaccines, DNA vaccines, and subunit vaccines (7)(8)(9)(10)(11)(12). Particularly, live vaccines are the closest alternative to natural pathogen infection, in addition to being powerful and eliciting durable immune responses (10). The two main types of live vaccines are attenuated and recombinant-vectored vaccines.…”

Protective immunity by DNA vaccine against Micropterus salmoides rhabdovirus

“…In 2019, the Chinese production of largemouth bass culture was up to 478,000 tons with an increase of 10.59% compared with 2018 (Zhang et al, 2021). Therefore, largemouth bass has been one of the important economic freshwater fish in China.…”

“…Its annual production has increased year after year, and the total global production of largemouth bass culture was about 458,000 tons in 2017, with China being the most important culture area, whose annual production accounts for about 99.8% of the total production (Hussein et al, 2020). In 2019, the Chinese production of largemouth bass culture was up to 478,000 tons with an increase of 10.59% compared with 2018 (Zhang et al, 2021). Therefore, largemouth bass has been one of the important economic freshwater fish in China.…”

An ambient-temperature stable nanoparticle-based vaccine for nasal application that confers long-lasting immunogenicity to carried antigens

“…The fusion of antigens from baculovirus to the occlusion bodies have also been attempted. Several antigens such as herpesvirus II ( 13 ), Mycobacterium bovis ( 14 ), porcine circovirus type 2 ( 15 ), foot-and-mouth disease virus ( 16 ), and many others ( 17 ) have been fused to the wild type polyhedrin gene to generate recombinant occlusion bodies. Mice immunized with the recombinant polyhedras produced antibodies that recognize the pathogen, and in some studies prevent the disease ( 15 , 18 ).…”