Porcine circovirus type 2 (PCV2) can cause immunosuppression on herds. PCV2, as an essential pathogen of PCV2-systemic disease (PCV2-SD), has caused considerable economic losses in pig industry worldwide. Here we review and address the evolution, viral protein and immunolesion of PCV2 and preventive techniques of PCV2-SD.
Animals ; Circoviridae Infections ; veterinary ; Circovirus ; genetics ; Phylogeny ; Swine ; Swine Diseases ; virology ; Viral Proteins ; genetics

One-day-old SPF chicks were inoculated with the Cux-l strain of chicken infectious anemia virus (CIAV), and the clinical development of disease and its macroscopic and microscopic alterations in the thymus and bone marrow, were observed. Tissue sections of thymus and bone marrow were stained using the streptavidin-biotin peroxidase method and examined under light microscope for evaluation of antigenic intensities in tissues. Those findings were then compared with blood parameters and ELISA results obtained through collected sera during sacrifice procedures. We sought to determine: the localization of viral antigens in thymus and bone marrow tissues after inoculation, the correlation between antigen intensities and hematologic, serologic and histopathologic findings, definitive diagnostic criteria using histopathologic and immunoperoxidase methods, and the reliability of these methods in the diagnosis of CIAV infection. For this purpose, 83, one-day-old SPF chicks were used. The birds were divided into experimental (n = 52) and control (n = 26) groups. A virus dose of TCID50 of 100,000/ml was administered intramuscularly to every bird in the experimental group. Based on the results of this study, we have suggested that clinical examination, along with macroscopic and microscopic evaluation of the thymus and bone marrow, maybe undertaken starting from day 7 post-inoculation (PI). ELISA, might be of value, as it might give consistent results starting from day 14 PI. However, the most reliable results were obtained through examination of thymus and bone marrow sections from infected birds stained by immunoperoxidase technique, as early as day 4 PI.
Animals ; Bone Marrow/*pathology ; *Chicken anemia virus ; Chickens ; Circoviridae Infections/pathology/*veterinary ; Immunoenzyme Techniques ; Poultry Diseases/*pathology ; Specific Pathogen-Free Organisms ; Thymus Gland/*pathology

The Cap gene of antisense strand of circovirus has the most variation of the genome, and encodes a capsid protein which has the main immunogenicity. The N-terminal of capsid protein makes up of nuclear localization signal which is involved with virus location. This review summarizes the research advance of Cap gene of circovirus in the sequence characteristics, its encoding capsid protein, basic functions of the capsid protein and its interaction with MKRN1 protein, Hsp40 protein, receptor protein gClqR and complement factor C1qB protein. This paper lays a theory foundation for the further study of the capsid protein in the aspects of viral attachment, replication and transportation.
Animals ; Capsid Proteins ; genetics ; immunology ; metabolism ; Circoviridae Infections ; veterinary ; virology ; Circovirus ; genetics ; immunology ; Genetic Variation ; Genome, Viral ; genetics ; Nuclear Localization Signals ; Protein Binding ; Virus Replication

Distribution and characterization of interlukin-10 (IL-10)-secreting cells in lymphoid tissues of pigs naturally infected with porcine circovirus type 2 (PCV2) were evaluated in accordance with PCV2 antigen detection. After screening a total of 56 pigs showing the symptoms of postweaning multisystemic wasting syndrome (PMWS), 15 pigs were PCV2 positive and 5 pigs, which showed stronger positive signals over multiples tissues were further investigated. This study showed that in PCV2-infected lymphoid tissues, particularly mandibular lymph node, spleen and tonsil, IL-10 expression was mainly localized in T-cell rich areas but rarely in B cell rich areas. IL-10 was highly expressed in bystander cells but rarely in PCV2-infected cells. Elevated IL-10 expression was predominantly associated with T cells, but rarely with B cells or with macrophages. The results of this study provide evidence for the role of IL-10 in chronic PCV2 infection and its relation to PCV2 antigen in affected tissues. Constantly elevated levels of IL-10 lead to immunosuppression in persistent and chronic viral infections. The increased IL-10 expression observed in PCV2 infection in this study suggests that IL-10-mediated immunosuppression may play an important role in the pathogenesis and maintenance of naturally occurring PCV2 infection.
Animals ; Circoviridae Infections/immunology/pathology/*veterinary ; Circovirus/*immunology ; Gene Expression Regulation/*immunology ; Immunohistochemistry/veterinary ; Interleukin-10/immunology/*secretion ; Lymphoid Tissue/immunology/*pathology/secretion ; Porcine Postweaning Multisystemic Wasting Syndrome/*immunology/pathology ; Republic of Korea ; Swine ; T-Lymphocytes/immunology

Porcine reproductive and respiratory syndrome virus(PRRSV)0, porcine circovirus type 2(PCV-2) and porcine parvovirus (PPV)0 infections were investigated as possible causes of the postweaning multisystemic wasting syndrome(PMWS). Specific primers for RT-PCR and PCR were designed for the differential detection of PRRSV, PCV-2 and PPV. Using PCR, these viruses were detected in homogenized tissue samples from pigs that had respiratory of reproductive problems in the time period between 1998 and 2000; the overall prevalences were: PRRSV 31.4%, PCV-2 46.5%, and PPV 8.1%. PCV-2 was also detected in aborted fetal tissues.
Aborted Fetus/virology ; Animals ; Base Sequence ; Circoviridae Infections/diagnosis/epidemiology/*veterinary ; Circovirus/genetics/isolation&purification ; DNA Primers ; Diagnosis, Differential ; Korea/epidemiology ; Parvoviridae Infections/diagnosis/epidemiology/*veterinary ; Parvovirus, Porcine/genetics/isolation&purification ; Polymerase Chain Reaction/methods/veterinary ; Porcine Reproductive and Respiratory Syndrome/diagnosis/*epidemiology ; Porcine respiratory and reproductive syndrome virus/genetics/isolation & purification ; Prevalence ; Respiratory Tract Infections/veterinary/virology ; Reverse Transcriptase Polymerase Chain Reaction/methods/veterinary ; Sequence Homology ; Swine ; Swine Diseases/diagnosis/*epidemiology ; Wasting Syndrome/*veterinary/virology

Porcine circovirus type 2 (PCV2) is closely related to the postweaning multisystemic wasting syndrome (PMWS). In this study, the pig serum and tissue samples collected from different regions of Hangzhou District in Zhejiang Province of China between 2003 and 2005 were analyzed by enzyme-linked immunosorbent assay (ELISA) for PCV2 antibody and by polymerase chain reaction (PCR) for ORF2 gene. The results show that out of 1250 randomly collected serum samples, 500 sera (40%) were seropositive for PCV2. PCR results demonstrate that Hangzhou PCV2 with more than 50% Chinese PCV2 strains and French PCV2 formed Cluster A. Only one PCV2 from Hangzhou belonged to Cluster B with some other Chinese PCV2 and Netherlands's isolates. Cluster C consisted of PCV2 isolates from China, US, Canada, UK and Germany. The results indicate that the PCV2 infection was widespread in Hangzhou.
Animals ; Antigens ; chemistry ; China ; Circoviridae Infections ; genetics ; veterinary ; Enzyme-Linked Immunosorbent Assay ; methods ; Humans ; Open Reading Frames ; Phylogeny ; Polymerase Chain Reaction ; methods ; Sequence Analysis, DNA ; Swine ; Swine Diseases ; genetics

In order to observe the effect of the immune and weight of chickens after use the attenuated vaccine with low dose of chicken infectious anemia virus (CIAV). In this study, the effects of low dose of CIAV on the weight of SPF chickens and NDV antibody production were observed by simulated experiments. The results showed that 10 EID50 and 5 EID50 CIAV per plume attenuated NDV vaccines were used to cause the weight loss of SPF chickens. Compared with the use of the non contaminated vaccine group, it has significant difference. And NDV antibody levels compared with the use of the non contaminated groups also decreased after use the vaccine with two doses of CIAV contaminated. It has significant difference. A certain proportion of CIAV antibody positive was detected at the beginning of the second week after use the NDV vaccine with two doses of CIAV contaminated. The detection of a high proportion of CIAV nucleic acid was detected in the first week after the use of a contaminated vaccine. The results of the study demonstrate the effects of CIAV pollution on the production and immune function of SPF chickens, and it is suggested that increasing the detection of viral nucleic acid can help save time and improve the detection rate in the detection of exogenous virus contamination by SPF chicken test method.
Animals ; Antibodies, Viral ; immunology ; Chicken anemia virus ; genetics ; immunology ; physiology ; Chickens ; Circoviridae Infections ; immunology ; veterinary ; virology ; Poultry Diseases ; immunology ; virology ; Specific Pathogen-Free Organisms ; Vaccines, Attenuated ; administration & dosage ; genetics ; immunology

Chicken anemia virus (CAV) is an important viral pathogen that causes anemia and severe immunodeficiency syndrome in chickens worldwide. In this study, a potential diagnostic monoclonal antibody against the CAV VP1 protein was developed which can precisely recognize the CAV antigen for diagnostic and virus recovery purposes. The VP1 gene of CAV encoding the N-terminus-deleted VP1 protein, VP1Nd129, was cloned into an Escherichia (E.) coli expression vector. After isopropyl-beta-D-thiogalactopyronoside induction, VP1Nd129 protein was shown to be successfully expressed in the E. coli. By performing an enzyme-linked immunoabsorbent assay using two coating antigens, purified VP1Nd129 and CAV-infected liver tissue lysate, E3 monoclonal antibody (mAb) was found to have higher reactivity against VP1 protein than the other positive clones according to the result of limiting dilution method from 64 clones. Using immunohistochemistry, the presence of the VP1-specific mAb, E3, was confirmed using CAV-infected liver and thymus tissues as positive-infected samples. Additionally, CAV particle purification was also performed using an immunoaffinity column containing E3 mAb. The monoclonal E3 mAb developed in this study will not only be very useful for detecting CAV infection and performing histopathology studies of infected chickens, but may also be used to purify CAV particles in the future.
Animals ; Antibodies, Monoclonal/biosynthesis/genetics/*immunology ; Antigens, Viral/analysis ; Capsid Proteins/genetics/*immunology ; Chicken anemia virus/genetics/*immunology ; *Chickens ; Circoviridae Infections/blood/immunology/*veterinary/virology ; Escherichia coli/genetics ; Immunohistochemistry/veterinary ; Liver/virology ; Mice ; Mice, Inbred BALB C ; Microscopy, Fluorescence/veterinary ; Poultry Diseases/blood/immunology/*virology ; Specific Pathogen-Free Organisms ; Thymus Gland/virology

PMWS is a new emerging disease in swine herds worldwide. Field isolates of PCV-2, a putative major causative agent of PMWS, were isolated and genetically characterized. Viral genome of two field isolates (PC201DJ and PC201SS) from pigs showing typical PMWS was sequenced. The nucleotide sequence homology with other PCV-2 isolates was ranging from 95% to 99% in complete viral genomic sequence. The highly conserved nonanucleotide motif of replication origin was identical to that of other PCV-2 isolates. To determine the genetic heterogeneity of PCV-2 isolates, the phylogenetic tree based on the complete genome of PCV-2 isolates were constructed. Two PCV-2 field isolates were closely related to Canadian isolates of PCV-2. PCV-2 isolated from field may have an origin of North America and is possibly originated from importation of breeding stocks. The result indicates that although the genome of PCV-2 is relatively stable in general, minor genetic variations exist among PCV-2 isolates from the different geographic locations. These differences of viral genome might have an important implication for genetic characteristics of PCV-2 infection. Three major immunorelevant epitopes of capsid protein showed variations in amino acid sequences. Also, the variance of amino acid sequence in antigenic epitope existed between two Korean PCV-2 isolates.
Animals ; Base Sequence ; Circoviridae Infections/*veterinary ; Circovirus/classification/genetics/*isolation & purification ; Cloning, Molecular ; Conserved Sequence ; DNA Primers ; Genome, Viral ; Korea ; Molecular Sequence Data ; Phylogeny ; Polymerase Chain Reaction ; Restriction Mapping ; Sequence Alignment ; Sequence Homology, Nucleic Acid ; Swine ; Swine Diseases/*virology ; Wasting Syndrome/*veterinary/virology ; Weaning

Porcine circovirus (PCV) type2 was isolated using primary porcine kidney cells from lymph node of piglets with typical PMWS. The presence of the virus was identified by PCR using primers specific to PCV type2. The ORFs 1 and 2 were amplified by PCR using primers corresponding to the target genes of the PCV type 2. Cloned genes were inserted into the baculovirus expression vector and PCV recombinant proteins were expressed using baculovirus expression system. Recombinant protein expression was determined by indirect immunofluorescent assay (IFA) and immunoblotting using polyclonal antiserum to PCV. ORF1 gene expressed two proteins with approximately 17 kDa and 31 kDa proteins in the baculovirus system. Recombinant protein of the ORF2 was similar to that of the native virus except minor bands with different molecular weight were detected. Recombinant protein expressed in the baculovirus system showed at least two glycosylation sites based on the tunicamycin treatment. Recombinant protein of the ORF2 assembled virus-like particle in recombinant virus infected insect cells.
Animals ; Baculoviridae/*genetics ; Blotting, Western ; Circoviridae Infections/*veterinary/*virology ; Circovirus/*classification/genetics/isolation & purification/ultrastructure ; Cloning, Molecular ; Fluorescent Antibody Technique, Indirect ; Lymph Nodes/virology ; Microscopy, Electron ; Open Reading Frames ; Palatine Tonsil/virology ; Polymerase Chain Reaction/methods/veterinary ; Recombinant Proteins/analysis ; Swine ; Swine Diseases/*virology ; Transfection ; Tunicamycin/pharmacology ; Viral Proteins/*analysis