ABSTRACT
Capsid protein (Cap), the only structural protein of porcine circovirus 2 (PCV2), is involved in the host protective response and is a target for vaccine development. To find a rapid and easy way to fully map the antigenic epitopes of Cap, purified Cap-specific polyclonal antibodies were used to screen a random heptapeptide phage display library. After three rounds of screening, twenty phage clones that had binding activity to Cap-specific antibodies (tested by phage ELISA) were sequenced. When the inserted amino acid sequences were aligned with the Cap protein sequence, eight core regions in Cap ((50)SRTFGYT(56), (62)VRTPSW(67), (68)AVDMMR(73), (79)FLPPGG(84), (86)SNPRSVPF(93), (102)KVEFWP(107), (119)GSSXXXLDDN(128) and (229)PPLNP(233)) were identified, three of which ((50)SRTFGYT(56), (86)SNPRSVPF(93) and (102)KVEFWP(107)) for the first time. Nine phagetopes representing the eight regions were chosen to immunize Kunming mice. All except minotopes (50)SRTFGYT(56) and (229)PPLNP(233) induced antibodies against PCV2 when injected into Kunming mice.
Subject(s)
Antibodies, Viral/immunology , Capsid Proteins/chemistry , Capsid Proteins/immunology , Circoviridae Infections/veterinary , Circovirus/immunology , Peptide Library , Swine Diseases/virology , Amino Acid Sequence , Animals , Capsid Proteins/genetics , Circoviridae Infections/immunology , Circoviridae Infections/virology , Circovirus/chemistry , Circovirus/genetics , Epitope Mapping , Mice , Molecular Sequence Data , Swine , Swine Diseases/immunologyABSTRACT
Outbreaks of classical swine fever (CSF) have caused serious economic consequences in China. Phylogenetic analysis based on full-length E2 gene sequences showed that five classical swine fever virus (CSFV) isolates collected from Hunan province in 2011 and 2012, together with seven other isolates from neighboring provinces, Guangdong (5) and Guangxi (2), could be classified as a new subgenotype 2.1c, which may have been endemic in the south of China for at least fourteen years. Subgenotype 2.1c isolates share 90.2-94.9% and 89.9-93.8% nucleotide sequence similarity separately with those of subgenotype 2.1a and 2.1b in E2 gene, which are lower than the nucleotide identities between subgenotype 2.1a and 2.1b (91.1-95.7%). Further analysis based on a partial E2 gene sequence (216 nt) indicated that subgenotype 2.1c isolates are also circulating in Thailand. Alignment of E2 amino acid sequences showed that subgenotype 2.1c isolates exhibit a SPA â TPV substitution at positions 777 and 779 compared with subgenotypes 2.1a and 2.1b.
Subject(s)
Classical Swine Fever Virus/classification , Classical Swine Fever Virus/genetics , Genotype , Phylogeny , Viral Envelope Proteins/genetics , Amino Acid Sequence , Animals , China/epidemiology , Classical Swine Fever/epidemiology , Classical Swine Fever/virology , Classical Swine Fever Virus/isolation & purification , Molecular Sequence Data , Sequence Alignment , Swine , Viral Envelope Proteins/chemistryABSTRACT
Circular genomes smaller than and similar to the genome of porcine circovirus 2 were obtained from pig tissues along with the full-length genome of porcine circovirus 2. The 922-, 839-, and 617-nucleotide-long genomes exhibit high homology to the rep gene plus the origin of replication sequence of porcine circovirus 2.
ABSTRACT
Two isolates of a new classical swine fever virus (CSFV) subgenotype, 2.1c (HNLY-2011 and HNSD-2012), were recently isolated from pigs in Hunan Province, China. The most significant difference in the amino acid sequences of the polyproteins from subgenotypes 2.1a and 2.1b is an SPA â TPV amino acid substitution at positions 777 and 779 in the E2 protein.
ABSTRACT
The seroprevalence of porcine cytomegalovirus (PCMV) and sapovirus (SaV) infections in pigs was investigated in Hunan province, China, between May 2005 and October 2010. A total of 500 pig serum samples collected from 10 representative administrative regions in Hunan province were evaluated for antibodies against PCMV and SaV using enzyme-linked immunosorbent assay (ELISA). The overall seroprevalence of porcine cytomegalovirus and sapovirus in pigs was 96.40% (482/500) and 63.40% (317/500), and the seropositivity of 10 herds we surveyed varied, ranging from 94.74% to 98.48% and 56.36% to 72.50%, respectively. The highest prevalence was found in breeding sows (96.67% for PCMV and 83.33% for SaVs). The results of the present survey indicated that infections with porcine cytomegalovirus and sapovirus are highly prevalent in pigs in Hunan province, China.
