Porcine circovirus 2
85708
PCV2 binds to heparin sulfate and chondroitin sulfate, which are glycosaminoglycans (GAGs), as a 1st step of attachment. However, as PCV2 is found in cells that lack GAGs, it is thought that another coreceptor is also used for viral entry. The hallmark lesion of PCV2 infection is lymphoid depletion with histiocytic replacement. In affected lymph organs, dendritic cells, and macrophages that replace the lymphocytes contain large amounts of PCV2 virus. There is no viral degradation in these cells, and because dendritic cells are highly mobile, it is thought that dendritic mobility may be a method of viral dissemination in tissues. It is still unknown how PCV2 causes a reduction in lymphocytes. Hypotheses include induced apoptosis, decreased lymphocyte production in the bone marrow, or reduced lymphocyte proliferation in secondary lymphoid tissue (Gillespie et al., 2009).
Postweaning multisystemic wasting syndrome
Because most breeding age sows are seropositive for PCV2, most piglets are born with maternal antibodies against PCV2. In weaned piglets, the mean half life of antibodies is 19 days. Antibody levels will wane at 4–6 weeks in pigs with initially low levels of antibody, at 6–10 weeks with moderate antibody levels, and by 8.5–13.5 weeks in pigs with high antibody levels. Piglets do not typically demonstrate clinical signs of disease before 4 weeks of age, suggesting that maternally derived antibodies are protective. Experimental studies found that maternal antibody protection is dependent on the level of maternal antibodies present. High levels of maternal antibodies are more protective than low levels, but do not completely prevent infection, whereas low levels of antibodies did not provide any protection against infection (Gillespie et al., 2009).
Porcine Circovirus (PCV) is a single stranded DNA virus (class II), that is non-enveloped with an un-segmented circular genome. The viral capsid is icosahedral and approximately 17 nm in diameter. PCV is a member of the virus family Circoviridae. PCV are the smallest viruses replicating autonomously in eukaryotic cells. They replicate in the nucleus of infected cells, utilising the host polymerase for genome amplification. There are 2 strains: Type 1 PCV and Type 2 PCV. It is still unclear whether type 2 PCV (first isolated in 1997) actually causes PMWS, as infection with the virus alone causes no clinical signs, it appears to work synergistically with parvovirus, perhaps with parvovirus activating a latent form of circovirus or weakening the immune system enough for PCV to take hold. PCV1 and PCV2 show a high degree of sequence identity and a similar genomic organisation; nevertheless, the basis of the distinct pathogenicity has not yet been unravelled (Wiki: Porcine circovirus).
Baboon
Papio cynocephalus
9556
Bank vole
Clethrionomys glareolus
447135
Bear
Ursus americanus
9643
Birds
Passeroidea
175121
Brown Trout
Salmo trutta
8032
Buffalo
Bison bison
9901
Carnivores
Vulpes
9625
Cat
Felis catus
9685
Catfishes
Siluriformes
7995
Cattle
Bos taurus
9913
Chicken
Gallus gallus
9031
Chimpanzee
Pan troglodytes
9598
chinchillas
Chinchillidae
10150
Copper Pheasant
Syrmaticus soemmerringii
9067
Deer
Cervus elaphus
9860
Deer mouse
Peromyscus maniculatus
10042
Dog
Canis familiaris
9615
Ducks
Anas
8835
Ferret
Mustela putorius furo
9669
Fish
Hyperotreti
117565
Gerbil
Gerbillina
10045
Goat
Capra hircus
9925
Gray wolf
Canis lupus
9612
Guinea pig
Cavia porcellus
10141
Hamster
Mesocricetus auratus
10036
Horse
Equus caballus
9796
Human
Homo sapiens
9606
Macaque
Macaca fascicularis
9541
Mongolian Gerbil
Meriones unguiculatus
10047
Monkey
Platyrrhini
9479
Mouse
Mus musculus
10090
None
None
Parrot
Psittacidae
9224
Pig
Sus scrofa
9823
Rabbit
Oryctolagus cuniculus
9986
Rainbow trout
Oncorhynchus mykiss
8022
Rat
Rattus
10114
Raven
Corvus corax
56781
sei whale
Balaenoptera borealis
9768
Sheep
Ovis aries
9940
Squirrel
Spermophilus richardsonii
37591
Tree shrew
Tupaiidae
9393
Trouts, salmons & chars
Salmoninae
504568
Turkey
Meleagris gallopavo
9103
Vole
Microtus ochrogaster
79684
Water buffalo
Bubalus bubalis
391902
BV-GD-ORF2
VO_0004754
Recombinant vector vaccine
Research
Intramuscular injection (i.m.)
B aculovirus was used to develop a novel candidate vaccine for a preventive or therapeutic strategy to control PCV2 infections (Ye et al., 2013).
Intramuscular injection (i.m.)
BALB/c mice were immunized intramuscularly with this baculovirus (Ye et al., 2013).
VO_0003057
The vaccination of mice with recombinant baculovirus BV-GD-ORF2 successfully induced robust Cap-protein-specific humoral and cellular immune responses (Ye et al., 2013).
PCV2 DNA Vaccine encoding ORF2 Protein
VO_0011481
DNA vaccine
Research
pCI-neo [Ref1247:Shen et al., 2008]
Intramuscular injection (i.m.)
Intramuscular injection (i.m.)
DNA vaccine construction
BALB/c
The mice in the vaccine groups were injected intramuscularly in the quadriceps with 100 µg pORF2 plasmid prepared in 100 µl PBS as follows. The mice in the pORF2 group received vaccination with pORF2 plasmid, three times every 2 weeks, whilst those in the pORF2/Cap or Cap/pORF2 group were primed with pORF2 plasmid (or Cap protein) and boosted with doses of Cap protein (or pORF2 plasmid) twice every 2 weeks (Shen et al., 2008).
Following virus challenge, real-time PCR and histopathological analysis confirmed that only low viral DNA loads and mild microscopic lesions appeared in pORF2-immunized mice (Shen et al., 2008).
At 16 weeks p.i., the mice were challenged intraperitoneally with 0.2 ml PCV2 inoculum (105.75 TCID50 1/ml) (Shen et al., 2008).
Serum IgG1 was significantly higher in mice immunized with PCV2 DNA vaccine encoding ORF2 protein than control mice, vaccinated with the pCI-neo vector and crude lysate of E. coli strain BL21 transformed with pGEX-4T-1 were used as substitutes for pORF2 plasmid and Cap protein, respectively. The up regulation began 4 weeks after immunization (Shen et al., 2008).
Serum IgG2a was significantly higher in mice immunized with PCV2 DNA vaccine encoding ORF2 protein than control mice, vaccinated with the pCI-neo vector and crude lysate of E. coli strain BL21 transformed with pGEX-4T-1 were used as substitutes for pORF2 plasmid and Cap protein, respectively. The up regulation began 4 weeks after immunization (Shen et al., 2008).
Porcilis-PCV2
Porcilis-PCV2
Intervet
VO_0000201
Inactivated or "killed" vaccine
Licensed
Intramuscular injection (i.m.)
Inactivated baculovirus expressed PCV2 ORF2 protein; adjuvanted (Wang et al., 2007).
Intramuscular injection (i.m.)
Porcine Circovirus Type 1 - Type 2 Chimera, Killed Virus Vaccine (USDA: 19K5.R1)
Wyeth
VO_0002195
Inactivated or "killed" vaccine
Licensed
USA
Porcine Circovirus Type 2, Killed Baculovirus Vector Vaccine (USDA: 19K5.R0)
Boehringer Ingelheim Vetmedica, Inc., Intervet Inc.
Inactivated or "killed" vaccine
Licensed
USA
Porcine Circovirus Type 2, Killed Baculovirus Vector Vaccine- Mycoplasma Hyopneumoniae Bacterin (USDA: 49K5.R1)
Boehringer Ingelheim Vetmedica, Inc.
VO_0002316
Inactivated or "killed" vaccine
Licensed
USA
Porcine Circovirus Type 2, Killed Virus Vaccine (USDA: 19K5.20)
Merial, Inc.
VO_0001798
Inactivated or "killed" vaccine
Licensed
USA
Porcine Reproductive & Respiratory Syndrome-Circovirus Reproductive & Respiratory Form, Type 2, Modifed Live Virus,Killed Baculovirus Vector Vaccine-Mycoplasma Hyopneumoniae Bacterin (USDA: 49K9.R0)
Boehringer Ingelheim Vetmedica, Inc.
VO_0002317
Live, attenuated vaccine; Inactivated or "killed" vaccine
Licensed
USA
PrV-PCV2-ORF2
VO_0004699
Recombinant vector vaccine
Research
Intramuscular injection (i.m.)
PCV2 ORF2 gene was inserted into vector pG to produce the recombinant PRV vector pGO (Chao et al., 2014).
Intramuscular injection (i.m.)
Recombinant vector construction
PCV2 ORF2 gene was inserted into vector pG to produce the recombinant PRV vector pGO; the genome of PRV attenuated vaccine and the transfer plasmid pGO were transfected by using Lipofectamine 2000 Reagent into swine testis cells for homologous recombination to obtain the recombinant PRV (Chao et al., 2014).
Six week odl mice were immunized two intramuscular immunizations 4 weeks apart (Chao et al., 2014).
VO_0003057
Challenge experiments show that the recombinant virus and PCV2 inactivated vaccine could both protect the mice against PCV2 challenge, suggesting that the recombinant virus can be an excellent potential vaccine (Chao et al., 2014).
Mice were then challenged with the virulent PCV2 NY strain at 8 weeks after the first immunization (Chao et al., 2014).
rSPV-PCV2-cap
recombinant swinepox virus expressing PCV2 capsid protein
VO_0004619
Recombinant vector vaccine
Research
[Ref3090:Lin et al., 2012]
Intramuscular injection (i.m.)
Recombinant swinepox virus expressing capsid protein (rSPV-cap) (Lin et al., 2012).
Intramuscular injection (i.m.)
PCV2 capsid
Pigs were immunized with rSPV-cap, wild type SPV (wtSPV; negative control), or PBS (challenge control) (Lin et al., 2012).
VO_0003057
After inoculation with PCV2, pigs in the rSPV-cap immunized group showed significantly higher average daily weight gain (ADG) and shorter fever duration compared with the wtSPV treated group. The results suggested that the recombinant rSPV-cap provided pigs with significant protection from PCV2-associated disease (Lin et al., 2012).
Vaccinated pigs were challenged with PCV2 (Lin et al., 2012).
Suvaxyn PCV2
Suvaxyn PCV2
Fort Dodge
VO_0000203
Inactivated or "killed" vaccine
Licensed
Intramuscular injection (i.m.)
Inactivated PCV1-2 chimera; adjuvanted (Ferrari et al., 2000)
Intramuscular injection (i.m.)
Ighg1
Mus musculus
16017
AC160982
Vaximmutor
Ighv1-9
Mus musculus
668478
AC073561
10090
12
114583568
114583861
immunoglobulin heavy variable V1-9
Also known as Igg2a; Gm16697
>gi|372099098:114583568-114583861 Mus musculus strain C57BL/6J chromosome 12, GRCm38 C57BL/6J
GTCTTGCACAGTAATAGATGGCAGAGTCCTCAGTTGTCAGGCTGCTGAGTTGCATGTAGGCTGTGTTGGA
GGATGTATCTGCAGTGAATGTGGCCTTGCCCTTGAACTTCTCATTGTAGTTAGTACTACCACTTCCAGGT
AAAATCTCTCCAATCCACTCAAGGCCATGTCCAGGCCTCTGCTTTACCCACTCTATCCAGTAGCCAGTGA
ATGTGTAGCCAGTAGCCTTGCAGGAAAGCTTCACTGAGGCCCCAGGCTTCATCAGCTCAGCTCCAGACTG
CTGCAGCTGAACCT
Vaximmutor
ORF2
Porcine circovirus type 2
VO_0011243
78217439
CDD:280582
85708
?
ORF2
11.34
26948.82
278
Circovirus capsid protein; pfam02443
>ABB36795.1 ORF2 [Porcine circovirus 2]
MAYPRRRYRRRRHRPRSHLGQILRRRLWLLHPRHRYRWRRKNGIFNTRLSRTFGYTIKRTTVKTPSWAVD
MMRFNINDFLPPGGGSNPRSVPFEYYRIRKVKVEFWPCSPITQGDRGVGSSAVILDDNFVTKATALTYDP
YVNYSSRHTITQPFSYHSRYFTPKPVLDSTIDYFQPNNKRNQLWLRLQTAGNVDHVGLGTAFENSIYDQE
YNIRVTMYVQFREFNLKDPPLKP
Protective antigen
An open reading frame 2 plasmid (pORF2) and the capsid protein (Cap) of PCV2 were used as DNA and subunit vaccines, respectively. In FCM analysis, although pORF2 and Cap alone showed comparable efficacy in eliciting lymphoproliferative responses and Cap-specific CD4(+) T cells, pORF2 was superior to the Cap protein in triggering CD8(+) T cells. Following virus challenge, real-time PCR and histopathological analysis confirmed that only low viral DNA loads and mild microscopic lesions appeared in pORF2-immunized mice [Ref1247:Shen et al., 2008].
Chao et al., 2014
journal
Chao A, Fu P, Guo X, Gao X, Cui B, Chen H
[Immune efficacy in mice by recombinant pseudorabies virus PGO expressing ORF2 gene of porcine circovirus type 2]
2014
54
2
211-217
Wei sheng wu xue bao = Acta microbiologica Sinica
Ding et al., 2017
journal
Ding P, Zhang T, Li Y, Teng M, Sun Y, Liu X, Chai S, Zhou E, Jin Q, Zhang G
Nanoparticle orientationally displayed antigen epitopes improve neutralizing antibody level in a model of porcine circovirus type 2
2017
12
5239-5254
International journal of nanomedicine
Ferrari et al., 2000
journal
Ferrari M, Brack A, Romanelli MG, Mettenleiter TC, Corradi A, Dal Mas N, Losio MN, Silini R, Pinoni C, Pratelli A
A study of the ability of a TK-negative and gI/gE-negative pseudorabies virus (PRV) mutant inoculated by different routes to protect pigs against PRV infection
2000
47
10
753-762
Journal of veterinary medicine. B, Infectious diseases and veterinary public health
Gillespie et al., 2009
journal
Gillespie J, Opriessnig T, Meng XJ, Pelzer K, Buechner-Maxwell V
Porcine circovirus type 2 and porcine circovirus-associated disease
2009
23
6
1151-1163
Journal of veterinary internal medicine / American College of Veterinary Internal Medicine
Lin et al., 2012
journal
Lin HX, Ma Z, Fan HJ, Lu CP
Construction and immunogenicity of recombinant swinepox virus expressing capsid protein of PCV2
2012
30
44
6307-6313
Vaccine
Shen et al., 2008
journal
Shen HG, Zhou JY, Huang ZY, Guo JQ, Xing G, He JL, Yan Y, Gong LY
Protective immunity against porcine circovirus 2 by vaccination with ORF2-based DNA and subunit vaccines in mice
2008
89
Pt 8
1857-1865
The Journal of general virology
Wang et al., 2007
journal
Wang X, Jiang P, Li Y, Jiang W, Dong X
Protection of pigs against post-weaning multisystemic wasting syndrome by a recombinant adenovirus expressing the capsid protein of porcine circovirus type 2
2007
121
3-4
215-224
Veterinary microbiology
Wiki: Porcine circovirus
website
Porcine circovirus
http://en.wikipedia.org/wiki/Porcine_circovirus
Xu et al., 2013
journal
Xu J, Yang D, Huang D, Xu J, Liu S, Lin H, Zhu H, Liu B, Lu C
Protection of guinea pigs by vaccination with a recombinant swinepox virus co-expressing HA1 genes of swine H1N1 and H3N2 influenza viruses
2013
158
3
629-637
Archives of virology
Ye et al., 2013
journal
Ye Y, Cheng X, Zhang J, Tong T, Lin W, Liao M, Fan H
Induction of robust immunity response in mice by dual-expression-system-based recombinant baculovirus expressing the capsid protein of porcine circovirus type 2
2013
10
316
Virology journal