Search

TLR8 is an important sensor of single-stranded RNA (ssRNA) from the viral genome and plays an essential role in innate antiviral responses via the recognition of conserved viral molecular patterns. In this report, TLR8 in the Chinese raccoon dog was characterized and analyzed for the first time. The full-length sequence of raccoon dog TLR8 (RdTLR8) cDNA was cloned by rapid amplification of cDNA ends (RACE) and is 3191bp with a 3117-bp open reading frame (ORF) encoding 1038 amino acids. The putative protein exhibits typical features of the TLR families, with 19 leucine-rich repeats (LRRs) in the extracellular domain and a cytoplasmic TIR domain. Comparative analyses of the RdTLR8 amino acid sequence indicated a 73.6–99.4% sequence identity with dog, horse, pig, sheep, cattle, human and mouse TLR8. Phylogenetic analysis grouped 71 mammalian TLR proteins into five sub-families, wherein RdTLR8 was clustered into a monophyletic TLR8 clade in the TLR9 family, which was completely coincident with the evolutionary relationship among mammals. Quantitative real-time PCR analysis revealed extensive expression of RdTLR8 in tissues from healthy Chinese raccoon dogs with the highest expression in the peripheral blood mononuclear cells (PBMCs) and the lowest expression in the skeletal muscle. HEK293 cells cotransfected with a RdTLR8 expression plasmid and an NF-κB-luciferase reporter plasmid significantly responded to the agonist 3M-002, indicating a functional TLR8 homolog. In addition, raccoon dog PBMCs exposed to the canine distemper virus (CDV) wild strain CDV-PS and the TLR8 agonist 3M-002 showed significant upregulation of RdTLR8 mRNA and proinflammatory cytokines TNF-α and IFN-α, suggesting that RdTLR8 might play an important role in the immune response to viral infections in the Chinese raccoon dog. [ABSTRACT FROM AUTHOR]

Canine parvovirus (CPV) type 2c is a new antigenic variant of CPV-2. Since the year 2000 it has spread to several countries, causing severe hemorrhagic enteritis in dogs. In 2014 and 2015, 58 fecal samples were collected from dogs in Beijing with suspected CPV infection. Regardless of the vaccination status of the dogs, 43 samples were found positive for CPV according to PCR results; i.e., 18, 7, and 18 respectively belonged to antigenic types new CPV-2a, new CPV-2b, and CPV-2c. A phylogenetic tree based on their VP2 gene sequences indicated that the Chinese CPV-2c strains form a separate cluster. In addition to synonymous mutations, the CPV-2c strains also contain a unique coding mutation in VP2 that leads to glycine at residue 5, instead of the highly conserved alanine at this position in all other CPV-2c strains sequenced to date. Using F81 cells, several novel isolates of CPV-2c, each with the Ala5Gly mutation, were obtained. One of these was used to infect experimentally beagle dogs, which subsequently developed the typical clinical symptoms of CPV infection. Hence, it appears that CPV-2c is still evolving in China, a finding that warrants continuous surveying and the eventual adaptation of current vaccines. [ABSTRACT FROM AUTHOR]

Abstracts Rabies has emerged as a serious problem in the most recent years in northern China. A rabies virus (RABV) isolate, IMDRV-13, was recovered from brain samples of dog-bitten rabid fallow deer ( Dama dama ) in a farm in Hohhot, Inner Mongolia. We tested the susceptibility of mouse neuroblastoma (MNA) cells and BSR cells as well as that of adult mice to IMDRV-13. The isolate was found to be a virulent isolate with an equivalent pathogenicity index (0.12) and a slight lower neurotropism index (1.07) compared with those of challenge virus standard, CVS-24, which was 0.13 and 1.23, respectively. The complete genome of IMDRV-13 was determined subsequently and found to be 11,924 nucleotides (nt) in length with the same genomic organization as other RABVs. Phylogenetic tree based on complete genome sequences of 43 RABV isolates and strains indicated that IMDRV-13, along with other two isolates in Inner Mongolia, CNM1101C and CNM1104D, clustered within the dog-associated China I clade, which is also the dominant lineage in the current rabies epidemic in China. In addition, sequence analysis of the glycoprotein G identified an amino acid substitution (I 338 → T 338 ) unique to the IMDRV-13 within antigenic sites III (330–338), this mutation also leads to an additional potential N -glycosylation site (N 336 ), which may represent a useful model to study relationship of N -glycosylation in G protein and specific properties such as pathogenicity or host adaption of RABV. [ABSTRACT FROM AUTHOR]

Bovine viral diarrhea virus (BVDV) is often detected in commercial bovine serum. BVDV genetic diversity was investigated in commercial bovine serum of Chinese origin. Twenty-two batches of bovine serum were obtained from 10 suppliers with different geographic origins in China, and 20 batches of bovine serum were positive by reverse-transcription polymerase chain reaction (RT-PCR) and sequencing. Phylogenetic reconstructions of partial 5′UTR sequences indicated that the samples examined in this work clustered within the BVDV type 1 and BVDV type 2 genotypes. Interestingly, 3 sample sequences clustered into CSFV. These results suggest a high genetic diversity in Chinese BVDV field isolates. This study will benefit epidemiological surveys of BVDV detected in China. [ABSTRACT FROM AUTHOR]

Abstract: In order to screen immunogenic candidate antigens for the development of a brucellosis subunit vaccine, an immunoproteomic assay was used to identify immunogenic proteins from Brucella melitensis 16M soluble proteins. In this study, a total of 56 immunodominant proteins were identified from the two-dimensional electrophoresis immunoblot profiles by liquid chromatography tandem mass spectrometry (LC–MS/MS). Two proteins of interest, riboflavin synthase alpha chain (RS-α) and Loraine synthase (LS-2), which are both involved in riboflavin synthesis, were detected by two-dimensional immunoblots using antisera obtained from Brucella-infected human and goats. LS-2, however, is an already well-known vaccine candidate. Therefore, we focussed our studies on the novel vaccine candidate RS-α. B. melitensis RS-α and LS-2 were then expressed in Escherichia coli as fusion proteins with His tag. The humoral and cellular immune responses to the recombinant (r)RS-α was characterized. In response to in vitro stimulation by rRS-α, splenocytes from mice vaccinated with rRS-α were able to produce γ-interferon (IFN-γ) and interleukin (IL)-2 but not interleukin (IL)-4 and interleukin (IL)-10. Furthermore, rRS-α or rLS-2-vaccinated mice were partially protected against B. melitensis infection. Our results suggested that we have developed a high-throughout, accurate, rapid and highly efficient method for the identification of candidate antigens by a combination of immunoproteomics with immunisation and bacterial challenge and rRs-α could be a useful candidate for the development of subunit vaccines against B. melitensis. [Copyright &y& Elsevier]