Complete Genomic Sequence of a Novel Porcine Circovirus 2 Strain, CC12.

The genome sequence of a novel porcine circovirus 2 strain (CC12) is composed of 1,767 nucleotides, with two major open reading frames (ORFs). ORF1 encodes two replication-associated proteins (Rep and Rep') with the unique mutation N186S, and ORF2 encodes a viral capsid protein (Cap) with two rare mutations, R59K and A190T.

ERIC-PCR genotyping of Pseudomonas aeruginosa isolates from haemorrhagic pneumonia cases in mink.

BACKGROUND: Pseudomonas aeruginosa is a significant pathogen of mink and the cause of haemorrhagic pneumonia, an acute fatal disease in farmed mink. RESULTS: Among 90 P. aeruginosa isolates from haemorrhagic pneumonia in mink from 16 farms in Shandong province, China, 43 genotypes were identified by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), with a diversity index of 0.96. The most prevalent ERIC-PCR types were type 18, found in 16 isolates, and type 39, found in 15 isolates. Four serotypes were detected, with serotype G (55.6 per cent) being the most frequent. CONCLUSIONS: These results showed that there was a high degree of clonal diversity among mink P. aeruginosa clinical isolates in this study.

Positive inductive effect of IL-18 on virus-specific immune responses induced by PRRSV-GP5 DNA vaccine in swine.

Two DNA vaccines encoding the envelope protein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) alone (pEGFP-GP5) and co-encoding GP5 and swine interleukin-18 (IL-18) proteins (pEGFP-IL18-GP5), were constructed and comparatively evaluated for their abilities to induce humoral and cellular responses in piglets. Experimental results showed that among all vaccinated groups, the live PRRSV vaccine elicited the highest titre of serum neutralizing antibody and the strongest cell-mediated immune responses, which means that the live PRRSV vaccine is still the first option for the vaccination against PRRSV. Moreover, the piglets inoculated with pEGFP-IL18-GP5 developed significantly higher IFN-γ production response, significantly increased percentages of CD4(+) and CD8(+) T-lymphocytes and significantly higher specific T-lymphocyte proliferation response than the pEGFP-GP5 inoculated pigs (P<0.05). These results demonstrated the positive inductive effect of IL-18 on the activation of cellular immune responses in swines. Therefore, in order to develop a new type vaccine for PRRS prevention and control, co-encoding of GP5 and IL-18 proteins may be a good choice.

Immune responses in pigs induced by recombinant DNA vaccine co-expressing swine IL-18 and membrane protein of porcine reproductive and respiratory syndrome virus.

In this study, two DNA vaccines, which express the membrane (M) protein of porcine respiratory and reproductive syndrome virus (PRRSV) (pEGFP-M) and co-express both M and swine IL-18 (pEGFP-IL18-M), were constructed and their abilities to induce humoral and cellular responses in piglets were comparatively evaluated. Experimental results showed that both recombinant DNA vaccines could not elicit neutralizing antibodies in the immunized piglets. However, both DNA vaccines elicited Th1-biased cellular immune responses. Notably, pigs immunized with the plasmid pEGFP-IL18-M developed significantly higher levels of IFN-γ and IL-2 production response and stronger specific T-lymphocyte proliferation response than the pigs inoculated with the plasmids pEGFP-M and pEGFP-IL18 (P < 0.05). These results illustrated that co-expression of M and IL-18 proteins could significantly improve the potency of DNA vaccination on the activation of vaccine-induced virus-specific cell-mediated immune responses in pigs, which may be used as a strategy to develop a new generation of vaccines against highly pathogenic PRRSV.

Overexpression of triosephosphate isomerase inhibits proliferation of chicken embryonal fibroblast cells.

Triosephosphate isomerase (TPI), a glycolytic enzyme, functions in catalyzing the interconversion of glyceraldehyde-3-phosphate and dihydroxyacetone phosphate and is generally upregulated in tumours. However, there are data suggesting loss in lymphomas. To determine its effects in chicken embryonal fibroblasts (CEF) a plasmid was constructed to allow transfection. Upon culture in a suitable medium, cells transfected with the TPI demonstrated upregulation and were significantly more susceptible to apoptosis compared to controls with decreased proliferation. These finding therefore render a novel mechanism by which CEF can be triggered to undergo death by upregulation of TPI.

Expression of interleukin 6 in brain and colon of rats with TNBS-induced colitis.

AIM: To characterise expression of interleukin 6 (IL-6), a potent proinflammatory cytokine, in the occurrence and development of inflammatory bowel disease (IBD) and investigate its effect on neuroimmunomodulation and immune homeostasis regulation. METHODS: In this study, rats with colitis induced by trinitrobenzene sulfonic acid (TNBS) were sacrificed on days 3, 7, 14, 21 and 28 after induction. In the controls, the TNBS was just replaced by equivalent amount of phosphate buffered solution (PBS, 0.01 mol/L). IL-6 mRNA expression in brain and colon tissues in each phase was evaluated by real-time reverse transcription-polymerase chain reaction, and cellular localisation and protein level of IL-6 was determined by immunohistochemistry. RESULTS: At day 7, mRNA expression of IL-6 was significantly higher in the colon and brain of IBD rats than that of the controls. The protein level was also significantly higher in colon, hypothalamus and cerebral cortex of IBD rats compared with the controls. So there are similar temporal trends in IL-6 mRNA expression and protein levels in all positions with a persistent increase to a peak at day 7, followed by a decline and gradual return to normal levels. CONCLUSION: These results revealed that changes in IL-6 expression in brain and colon tissues occur in different phases of IBD. Therefore, we propose that the nerve centre regulates and controls the occurrence and development of IBD via IL-6.

Antigenic variation between Newcastle disease viruses of goose and chicken origin.

Newcastle disease virus (NDV) is believed to infect only domestic avian species, with waterfowl such as geese either not being infected, even by virulent strains, or developing only inapparent infection. Since the late 1990s, a new infectious disease producing high morbidity and mortality among geese broke out in many provinces of China. This disease was caused by a serotype I avian paramyxovirus known as (APMV-1)-NDV. To investigate how NDV spreads between chickens and geese, the serological similarities of NDV strains (goose-origin NDV/NA-1 and chicken-origin NDV/F48E9, F48E8) were assessed by cross-neutralization assays both in vivo and in vitro. The results indicated that antigenic variation had occurred between NDV/NA-1 strains and NDV/F48E9, F48E8 strains. Notably, NDV/NA-1 effectively protected vaccinated birds from morbidity and mortality against NDV/NA-1 strain challenge and significantly reduced virus shedding from the vaccinated birds when compared with F48E9-vaccinated birds. This might provide clues to the evolution of the goose NDV.

Inhibition of Newcastle disease virus replication by RNA interference targeting the matrix protein gene in chicken embryo fibroblasts.

Newcastle disease (ND) is an infectious viral disease of birds caused by the Newcastle disease virus (NDV), also known as avian paramyxovirus type 1 (AMPV-1), which leads to severe economic losses in the poultry industry worldwide. In this study, the application of RNA interference (RNAi) for inhibiting the replication of NDV in cell culture by targeting the viral matrix protein gene (M) is described. Two M-specific shRNA-expressing plasmid constructs, named pS(M641) and pS(M827), were evaluated for antiviral activity against the NDV strain NA-1 by cytopathic effects (CPE), virus titration and real-time RT-PCR. After 36h of infection, both pS(M641) and pS(M827) reduced virus titers by 79.4- and 31.6-fold, respectively, and they down-regulated mRNA expression levels of the matrix protein gene M by 94.6% and 84.8%, respectively, in chicken embryo fibroblast (CEF) cells, while only pS(M641) significantly decreased CPE, compared to the control group. These results indicated that the M gene 641 and 827 sites represent potential antiviral therapy targets, and RNAi targeting of the M gene could not only represent an effective treatment in Newcastle disease but also aid as a method for studying the replication of NDV.