Coatsome-replicon vehicles: Self-replicating RNA vaccines against infectious diseases.

Herein, we provide the first description of a synthetic delivery method for self-replicating replicon RNAs (RepRNA) derived from classical swine fever virus (CSFV) using a Coatsome-replicon vehicle based on Coatsome® SS technologies. This results in an unprecedented efficacy when compared to well-established polyplexes, with up to ∼65 fold-increase of the synthesis of RepRNA-encoded gene of interest (GOI). We demonstrated the efficacy of such Coatsome-replicon vehicles for RepRNA-mediated induction of CD8 T-cell responses in mice. Moreover, we provide new insights on physical properties of the RepRNA, showing that the removal of all CSFV structural protein genes has a positive effect on the translation of the GOI. Finally, we successfully engineered RepRNA constructs encoding a porcine reproductive and respiratory syndrome virus (PRRSV) antigen, providing an example of antigen expression with potential application to combat viral diseases. The versatility and simplicity of modifying and manufacturing these Coatsome-replicon vehicle formulations represents a major asset to tackle foreseeable emerging pandemics.

African Horse Sickness Virus Serotype 1 on Horse Farm, Thailand, 2020.

To investigate an outbreak of African horse sickness (AHS) on a horse farm in northeastern Thailand, we used whole-genome sequencing to detect and characterize the virus. The viruses belonged to serotype 1 and contained unique amino acids (95V,166S, 660I in virus capsid protein 2), suggesting a single virus introduction to Thailand.

Allergen components of Dermatophagoides farinae recognised by serum immunoglobulin (Ig)E in Thai dogs with atopic dermatitis.

BACKGROUND: Dermatophagoides farinae (Der f) is a common allergen in dogs with atopic dermatitis (AD). However, the relevant components of Der f require further investigation. OBJECTIVES: We aimed to provide data on the immunoglobulin (Ig)E-binding specific components of Der f for further diagnostic and therapeutic applications. ANIMALS: Serum samples were collected from five healthy, nine Der f-allergic atopic and seven non-Der f-allergic atopic dogs identified based on an intradermal skin test. METHODS AND MATERIALS: We explored the component profiles of Der f extracts through 2D gel electrophoresis and IgE immunoblotting. The IgE-binding components in both groups of atopic dogs were analysed by mass spectrometry. RESULTS: The majority of Der f-allergic atopic dogs recognised Der f Alternaria alternata allergen 10 (Der f Alt a 10), elongation factor 1-alpha (EF1-α), gelsolin-like allergen Der f 16, Der f 28 and Der f 2. Der f 3, Der f 10, Der f 20 and Der f 32 were recognised as minor allergens. Alpha-enolase, serine protease, arginine kinase and a few hypothetical proteins were recognised components in both groups of atopic dogs. Unexpectedly, Der f 15 (chitinase) was found to be a minor component. CONCLUSIONS AND CLINICAL IMPORTANCE: Multiple IgE-binding allergens of Der f were identified in Thai atopic dogs. We propose that the specific antigen set that is bound by IgE, comprising Der f Alt a 10, EF1-α, gelsolin-like Der f 16, Der f 28 and Der f 2, could be used for future diagnostics and immunotherapy platforms.

Efficacy of a type 2 PRRSV modified live vaccine (PrimePac™ PRRS) against a Thai HP-PRRSV challenge.

The Chinese highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) has caused a severe threat to the pig population in Southeast Asian countries. The purpose of this study was to investigate the efficacy of a type 2 PRRSV modified live vaccine (PrimePac™ PRRS, lineage 7) against a Thai HP-PRRSV (10PL01, lineage 8). Three-week-old PRRSV-free pigs were randomly assigned into three groups. Vaccinated challenged group (group 1, n = 16) was immunized with PrimePac™ PRRS vaccine at 3 weeks old. The unvaccinated challenged group (group 2, n = 16) was injected with PBS at 3 weeks old, and unvaccinated unchallenged group (group 3, n = 10) was served as a negative control. At 9 weeks old, all groups, except the negative control group, were challenged with the Thai HP-PRRSV. All pigs were monitored daily during 10 days post-infection (dpi) and were necropsied at 10 and 17 dpi. The results revealed that vaccinated challenged pigs showed significantly lower (p < 0.05) mean rectal temperatures, clinical respiratory scores, lung lesion scores, and levels of virus load in serum and lung tissue compared with the unvaccinated challenged pigs. Moreover, vaccinated challenged pigs exhibited PRRSV-specific serum neutralizing antibodies at the end of the experiment. Our findings indicated that the studied type 2 PRRSV vaccine provided partial protection against the Thai HP-PRRSV infection based on the body temperature, levels of viremia, and the severity of lung lesions. These results demonstrated that partial protection of PrimePac™ PRRS vaccine might be useful for controlling HP-PRRSV infection in the endemic area.

Interleukin-1 receptor antagonist: an early immunomodulatory cytokine induced by porcine reproductive and respiratory syndrome virus.

Porcine reproductive and respiratory syndrome virus (PRRSV) infection poorly induces pro-inflammatory cytokines (IL-1, IL-6 and TNF-α) and type I IFN production during the early phase of infection. Our microarray analysis indicated strong upregulation of the IL1RA gene in type 2 PRRSV -infected monocyte-derived dendritic cells. Interleukin-1 receptor antagonist (IL-1Ra) is an early inhibitory cytokine that suppresses pro-inflammatory cytokines and T-lymphocyte responses. To investigate the induction of IL-1Ra by PRRSV, monocyte-derived dendritic cells were cultured with type 2 PRRSV or other swine viruses. PRRSV increased both IL1RA gene expression and IL-1Ra protein production in the culture. The enhanced production of IL-1Ra was further confirmed in PRRSV-cultured PBMC and PRRSV-exposed pigs by flow cytometry. Myeloid cell population appeared to be the major IL-1Ra producer both in vitro and in vivo. In contrast to the type 2 PRRSV, the highly pathogenic (HP)- PRRSV did not upregulate IL1RA gene expression in vitro. To determine the kinetics of PRRSV-induced IL1RA gene expression in relation to other pro-inflammatory cytokine genes, PRRSV-negative pigs were vaccinated with a commercially available type 2 modified-live PRRS vaccine or intranasally inoculated with HP-PRRSV. In modified-live PRRS vaccine pigs, upregulation of IL1RA, but not IL1B and IFNA, gene expression was observed from 2 days post- vaccination. Consistent with the in vitro findings, upregulation of IL1RA gene expression was not observed in the HP-PRRSV-infected pigs throughout the experiment. This study identified IL-1Ra as an early immunomodulatory mediator that could be involved in the immunopathogenesis of PRRSV infections.

Genetic characterization of canine influenza A virus (H3N2) in Thailand.

In January 2012, several clinical cases of dogs with flu-like symptoms, including coughing, sneezing, nasal discharge, and fever, were reported in a small-animal hospital located in Bangkok, Thailand. One influenza A virus was identified and characterized as an avian-like influenza virus H3N2. The virus was named A/canine/Thailand/CU-DC5299/12. A phylogenetic analysis indicated that the canine virus belonged to an avian Eurasian lineage and was genetically related to the canine influenza viruses H3N2 from China and Korea. This canine virus displays a unique genetic signature with two amino acid insertions in the NA protein, which is similar to the canine influenza viruses from eastern China (Zhejiang and Jiangsu). This study constitutes the first report of H3N2 canine influenza virus infection in a small-animal hospital in Thailand.

New Generation Self-Replicating RNA Vaccines Derived from Pestivirus Genome.

While mRNA vaccines have shown their worth, they have the same failing as inactivated vaccines, namely they have limited half-life, are non-replicating, and therefore limited to the size of the vaccine payload for the amount of material translated. New advances averting these problems are combining replicon RNA (RepRNA) technology with nanotechnology. RepRNA are large self-replicating RNA molecules (typically 12-15 kb) derived from viral genomes defective in at least one essential structural protein gene. They provide sustained antigen production, effectively increasing vaccine antigen payloads over time, without the risk of producing infectious progeny. The major limitations with RepRNA are RNase-sensitivity and inefficient uptake by dendritic cells (DCs), which need to be overcome for efficacious RNA-based vaccine design. We employed biodegradable delivery vehicles to protect the RepRNA and promote DC delivery. Condensing RepRNA with polyethylenimine (PEI) and encapsulating RepRNA into novel Coatsome-replicon vehicles are two approaches that have proven effective for delivery to DCs and induction of immune responses in vivo.

Impacts of shelter management on canine rabies immune status.

Rabies vaccination is mandatory in dogs in Thailand. In this study, shelter management quality and rabies immune status were evaluated by questionnaire and rabies virus neutralising antibody (RVNA) measurement. The questionnaire was designed to assess all relevant factors of shelter management, which could impact the rabies vaccine antibody response. Thirteen participating shelters were classified into 4 groups, namely group A (best), B (good), C (fair), and D (require improvement). Sera were collected from randomly selected dogs (n = 113) within 4 weeks after rabies re-vaccination from a representative shelter of group B, C and D. Sample from group A was not included in the study due to time limitation. Both the number of dogs with acceptable response (RVNA ≥ 0.5 IU/ml) and the RVNA titres were significantly higher in group B than group C and D. Our results indicate that the quality of shelter management could affect rabies immune status.

Role of porcine reproductive and respiratory syndrome virus nucleocapsid protein in induction of interleukin-10 and regulatory T-lymphocytes (Treg).

Porcine reproductive and respiratory syndrome virus (PRRSV) infection induces interleukin (IL)-10 production and increased numbers of PRRSV-specific regulatory T-lymphocytes in infected pigs. In the present study, the roles of the nucleocapsid (N) protein in induction of IL-10 and CD4(+)CD25(+)Foxp3(+) lymphocytes (T(reg)) were investigated. Transfection of porcine monocyte-derived dendritic cells (MoDCs) and pulmonary alveolar macrophages (PAMs) with a plasmid encoding N protein resulted in significant upregulation of IL-10 gene expression in the gene-transfected cells. Structural conformation, but not nuclear localization, of the expressed N protein was indicated to be essential for the ability to induce IL-10. Furthermore, the presence of recombinant N proteins in cultured PBMCs increased the number of IL-10-producing lymphocytes. Strong induction of IL-10-producing cells and T(reg) was observed when using N protein-pulsed MoDCs, suggesting an important role of MoDCs in induction of IL-10 and T(reg) by the N protein. Neutralization of IL-10 by addition of an anti-IL-10 antibody in the culture system resulted in marked reduction of PRRSV-induced T(reg) in the cultured PBMCs. Together, the data demonstrate the immunomodulatory properties of the PRRSV N protein and the linkage between IL-10 production and development of PRRSV-induced T(reg). Our results reveal an immunomodulatory function of the PRRSV N protein that may contribute to the unique immunological outcome observed following PRRSV infection.

Dynamics of cellular and humoral immune responses following duck Tembusu virus infection in ducks.

Duck Tembusu virus (DTMUV), an emerging avian pathogenic flavivirus, causes severe neurological disorders and acute egg drop syndrome in ducks. However, the effects of DTMUV on duck immunological components and functions remain largely unknown. In this study, the dynamics of cellular and humoral immune responses of DTMUV-infected ducks were investigated. The numbers of CD4+ and CD8+ T, B and non-T and B lymphocytes as well as the levels of neutralizing antibodies were quantified in parallel with DTMUV loads in blood and target organs. Our results demonstrated that DTMUV infection caused severe losses of non-T and B lymphocyte/myeloid cell subpopulation, and reduction in phagocytic activity during 3-5 days after infection. We also found that the numbers of T and B cells were increased during the first week of DTMUV infection. A significant negative correlation between the levels of CD4+ and CD8+ T, B and non-T and B lymphocytes and viral loads in blood and target organ (spleen) was observed during the early phase of infection. Additionally, DTMUV infection induced an early and robust neutralizing antibody response, which was associated with DTMUV-specific IgM and IgG responses. The presence of neutralizing antibody also correlated with reduction of viremia and viral load in the spleen. Overall, DTMUV elicited both cellular and humoral immune responses upon infection, in which the magnitude of these responses was correlated with reduction of viremia and viral loads in the target organ (spleen). The results suggested the critical role of both cellular and humoral immunity against DTMUV infection. This study expands our understanding of the immunological events following DTMUV infection in ducks.

Perspectives on veterinary education in Thailand.

Veterinary education is the foundation of veterinary services in the country. Starting from the service sector in the army, veterinary education and practice in Thailand have been standardized and progressed toward international veterinary standards. The 6-year Doctor of Veterinary Medicine core curriculum is deployed to develop the curriculum for each Veterinary Education Establishment (VEE). The challenges for veterinary education and practices reflect the country's expectations of veterinary services. With regional and global collaboration, the VEEs have been developing tools and learning platforms for delivering qualified veterinary graduates that fit fast-growing society needs.

Brief report: Molecular characterization of a novel reassorted pandemic H1N1 2009 in Thai pigs.

For the past 10 years, endemic swine influenza H1 viruses in Thailand have been characterized as reassortants of swine virus genes from swine influenza viruses (SIV) in US and European pigs. Here the authors report the emergence of a novel reassorted H1N1 (rH1N1) virus consisted of human, avian, and swine virus genes from the pandemic H1N1 2009 (pH1N1) virus with a neuraminidase (NA) gene from a Thai swine H1N1 (ThH1N1) isolate. The rH1N1 virus was detected in nursery pigs during a respiratory disease outbreak in central Thailand in early 2010. The rH1N1 virus was repeatedly isolated from infected pigs, suggesting that it can transmit efficiently among the pig population. The appearance of rH1N1 virus in the field occurred within months of the introduction of pH1N1 virus into the Thai swine population in late 2009. The finding highlights the role of pig in generating newly reassorted influenza A viruses and also the significance of continuing disease surveillance and genetic characterization of SIV in pigs.

Diversity of the Swine Leukocyte Antigen Class I and II in Commercial Pig Populations.

Among swine genetic markers, the highly polymorphic swine leukocyte antigen (SLA) is one of the key determinants, associated with not only immune responses but also reproductive performance and meat quality. The objective of this study was to characterize the SLA class I and II diversities in the commercial pig populations. In this study, a total number of 158 pigs (126 gilts and 32 boars) were randomly selected from different breeding herds of five major pig-producing companies, which covered ~70% of Thai swine production. The results indicate that a moderate level of SLA diversity was maintained in the Thai swine population, despite the performance-oriented breeding scheme. The highly common SLA class I alleles were SLA-1*08:XX, SLA-2*02:XX, and SLA-3*04:XX at a combined frequency of 30.1, 18.4, and 34.5%, respectively, whereas DRB1*04:XX, DQB1*02:XX and DQA*02:XX were the common class II alleles at 22.8, 33.3, and 38.6%, respectively. The haplotype Lr-32.0 (SLA-1*07:XX, SLA-2*02:XX, and SLA-3*04:XX) and Lr-0.23 (DRB1*10:XX, DQB1*06:XX, DQA* 01:XX) was the most common SLA class I and II haplotype, at 15.5 and 14.6%, respectively. Common class I and II haplotypes were also observed, which Lr-22.15 was the most predominant at 11.1%, followed by Lr-32.12 and Lr-4.2 at 10.8 and 7.9%, respectively. To our knowledge, this is the first report of SLA class I and II diversities in the commercial pigs in Southeast Asia. The information of the common SLA allele(s) in the population could facilitate swine genetic improvement and future vaccine design.

Two decades of one health surveillance of Nipah virus in Thailand.

BACKGROUND: Nipah virus (NiV) infection causes encephalitis and has > 75% mortality rate, making it a WHO priority pathogen due to its pandemic potential. There have been NiV outbreak(s) in Malaysia, India, Bangladesh, and southern Philippines. NiV naturally circulates among fruit bats of the genus Pteropus and has been detected widely across Southeast and South Asia. Both Malaysian and Bangladeshi NiV strains have been found in fruit bats in Thailand. This study summarizes 20 years of pre-emptive One Health surveillance of NiV in Thailand, including triangulated surveillance of bats, and humans and pigs in the vicinity of roosts inhabited by NiV-infected bats. METHODS: Samples were collected periodically and tested for NiV from bats, pigs and healthy human volunteers from Wat Luang village, Chonburi province, home to the biggest P. lylei roosts in Thailand, and other provinces since 2001. Archived cerebrospinal fluid specimens from encephalitis patients between 2001 and 2012 were also tested for NiV. NiV RNA was detected using nested reverse transcription polymerase chain reaction (RT-PCR). NiV antibodies were detected using enzyme-linked immunosorbent assay or multiplex microsphere immunoassay. RESULTS: NiV RNA (mainly Bangladesh strain) was detected every year in fruit bats by RT-PCR from 2002 to 2020. The whole genome sequence of NiV directly sequenced from bat urine in 2017 shared 99.17% identity to NiV from a Bangladeshi patient in 2004. No NiV-specific IgG antibodies or RNA have been found in healthy volunteers, encephalitis patients, or pigs to date. During the sample collection trips, 100 community members were trained on how to live safely with bats. CONCLUSIONS: High identity shared between the NiV genome from Thai bats and the Bangladeshi patient highlights the outbreak potential of NiV in Thailand. Results from NiV cross-sectoral surveillance were conveyed to national authorities and villagers which led to preventive control measures, increased surveillance of pigs and humans in vicinity of known NiV-infected roosts, and increased vigilance and reduced risk behaviors at the community level. This proactive One Health approach to NiV surveillance is a success story; that increased collaboration between the human, animal, and wildlife sectors is imperative to staying ahead of a zoonotic disease outbreak.

Pandemic (H1N1) 2009 virus on commercial swine farm, Thailand.

A swine influenza outbreak occurred on a commercial pig farm in Thailand. Outbreak investigation indicated that pigs were co-infected with pandemic (H1N1) 2009 virus and seasonal influenza (H1N1) viruses. No evidence of gene reassortment or pig-to-human transmission of pandemic (H1N1) 2009 virus was found during the outbreak.

Genetic characterization of 2008 reassortant influenza A virus (H5N1), Thailand.

In January and November 2008, outbreaks of avian influenza have been reported in 4 provinces of Thailand. Eight Influenza A H5N1 viruses were recovered from these 2008 AI outbreaks and comprehensively characterized and analyzed for nucleotide identity, genetic relatedness, virulence determinants, and possible sites of reassortment. The results show that the 2008 H5N1 viruses displayed genetic drift characteristics (less than 3% genetic differences), as commonly found in influenza A viruses. Based on phylogenetic analysis, clade 1 viruses in Thailand were divided into 3 distinct branches (subclades 1, 1.1 and 1.2). Six out of 8 H5N1 isolates have been identified as reassorted H5N1 viruses, while other isolates belong to an original H5N1 clade. These viruses have undergone inter-lineage reassortment between subclades 1.1 and 1.2 and thus represent new reassorted 2008 H5N1 viruses. The reassorted viruses have acquired gene segments from H5N1, subclade 1.1 (PA, HA, NP and M) and subclade 1.2 (PB2, PB1, NA and NS) in Thailand. Bootscan analysis of concatenated whole genome sequences of the 2008 H5N1 viruses supported the reassortment sites between subclade 1.1 and 1.2 viruses. Based on estimating of the time of the most recent common ancestors of the 2008 H5N1 viruses, the potential point of genetic reassortment of the viruses could be traced back to 2006. Genetic analysis of the 2008 H5N1 viruses has shown that most virulence determinants in all 8 genes of the viruses have remained unchanged. In summary, two predominant H5N1 lineages were circulating in 2008. The original CUK2-like lineage mainly circulated in central Thailand and the reassorted lineage (subclades 1.1 and 1.2) predominantly circulated in lower-north Thailand. To prevent new reassortment, emphasis should be put on prevention of H5N1 viruses circulating in high risk areas. In addition, surveillance and whole genome sequencing of H5N1 viruses should be routinely performed for monitoring the genetic drift of the virus and new reassorted strains, especially in light of potential reassortment between avian and mammalian H5N1 viruses.

Abrogation of PRRSV infectivity by CRISPR-Cas13b-mediated viral RNA cleavage in mammalian cells.

CRISPR/Cas9 enables dsDNA viral genome engineering. However, the lack of RNA targeting activities limits the ability of CRISPR/Cas9 to combat RNA viruses. The recently identified class II type VI CRISPR/Cas effectors (Cas13) are RNA-targeting CRISPR enzymes that enable RNA cleavage in mammalian and plant cells. We sought to knockdown the viral RNA of porcine reproductive and respiratory syndrome virus (PRRSV) directly by exploiting the CRISPR/Cas13b system. Effective mRNA cleavage by CRISPR/Cas13b-mediated CRISPR RNA (crRNA) targeting the ORF5 and ORF7 genes of PRRSV was observed. To address the need for uniform delivery of the Cas13b protein and crRNAs, an all-in-one system expressing Cas13b and duplexed crRNA cassettes was developed. Delivery of a single vector carrying double crRNAs enabled the simultaneous knockdown of two PRRSV genes. Transgenic MARC-145 cells stably expressing the Cas13b effector and crRNA mediated by lentiviral-based transduction showed a robust ability to splice the PRRSV genomic RNA and subgenomic RNAs; viral infection was almost completely abrogated by the combination of double crRNAs simultaneously targeting the ORF5 and ORF7 genes. Our study indicated that the CRISPR/Cas13b system can effectively knockdown the PRRSV genome in vitro and can potentially be used as a potent therapeutic antiviral strategy.

Comparative analysis of complete nucleotide sequence of porcine reproductive and respiratory syndrome virus (PRRSV) isolates in Thailand (US and EU genotypes).

BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) is a causative agent of Porcine Reproductive and Respiratory Syndrome (PRRS). In this study, the complete nucleotide sequences of the selected two Thai PRRSV isolates, EU (01CB1) and US (01NP1) genotypes were determined since both isolates are the Thai prototypes. RESULTS: 01CB1 and 01NP1 contain 14,943 and 15,412 nucleotides, respectively. The viruses compose 2 untranslated regions (5' UTR and 3' UTR) and 8 open reading frames (ORFs) designated as ORF1a, ORF1b and ORF2-7. Phylogenetic analysis of full length of the viruses also showed that the 01CB1 and 01NP1 were grouped into the EU and US genotype, respectively. In order to determine the genetic variation and genetic relatedness among PRRSV isolates, the complete nucleotide sequences of PRRSV isolated in Thailand, 01CB1 and 01NP1 were compared with those of 2 EU strains (Lelystad, and EuroPRRSV), 6 US strains (MLV, VR2332, PA8, 16244B, SP and HUN4). Our results showed that the 01CB1 genome shares approximately 99.2% (Lelystad) and 95.2% (EuroPRRSV) nucleotide identity with EU field strains. While, the 01NP1 genome has 99.9% nucleotide identity with a live vaccine strain (MLV) and 99.5% and 98.5% nucleotide identity with 2 other US isolates, VR2332 and 16244B, respectively. In addition, ORF5 nucleotide sequences of 9 PRRS viruses recovered in Thailand during 2002-2008 were also included in this study. Phylogenetic analysis of ORF5 showed high similarity among EU and US genotypes of the recent Thai PRRS viruses (2007-2008 viruses) with 01CB1 and 01NP1. CONCLUSION: Overall, the results suggested that the Thai EU isolate (01CB1) may evolve from the EU prototype, Lelystad virus, whereas the Thai US isolate (01NP1) may originate and evolve from the vaccine virus or its derivatives. Interestingly, the US-MLV vaccine was not available in the Thai market in 2001. The Vaccine-like virus might have persisted in the imported pigs or semen and later spread in the Thai swine industry. This report is the first report of complete nucleotide sequences of the Thai PRRS viruses both EU and US genotypes.

Negative Immunomodulatory Effects of Type 2 Porcine Reproductive and Respiratory Syndrome Virus-Induced Interleukin-1 Receptor Antagonist on Porcine Innate and Adaptive Immune Functions.

Impaired innate and adaptive immune responses are evidenced throughout the course of PRRSV infection. We previously reported that interleukin-1 receptor antagonist (IL-1Ra) was involved in PRRSV-induced immunosuppression during an early phase of infection. However, the exact mechanism associated with PRRSV-induced IL-1Ra immunomodulation remains unknown. To explore the immunomodulatory properties of PRRSV-induced IL-1Ra on porcine immune functions, monocyte-derived dendritic cells (MoDC) and leukocytes were cultured with type 2 PRRSV, and the immunological role of IL-1Ra was assessed by addition of anti-porcine IL-1Ra Ab. The results demonstrated that PRRSV-induced IL-1Ra reduced phagocytosis, surface expression of MHC II (SLA-DR) and CD86, as well as downregulation of IFNA and IL1 gene expression in the MoDC culture system. Interestingly, IL-1Ra secreted by the PRRSV-infected MoDC also inhibited T lymphocyte differentiation and proliferation, but not IFN-γ production. Although PRRSV-induced IL-1Ra was not directly linked to IL-10 production, it contributed to the differentiation of regulatory T lymphocytes (Treg) within the culture system. Taken together, our results demonstrated that PRRSV-induced IL-1Ra downregulates innate immune functions, T lymphocyte differentiation and proliferation, and influences collectively with IL-10 in the Treg induction. The immunomodulatory roles of IL-1Ra elucidated in this study increase our understanding of the immunobiology of PRRSV.

Influenza virus (H5N1) in live bird markets and food markets, Thailand.

A surveillance program for influenza A viruses (H5N1) was conducted in live bird and food markets in central Thailand during July 2006-August 2007. Twelve subtype H5N1 viruses were isolated. The subtype H5N1 viruses circulating in the markets were genetically related to those that circulated in Thailand during 2004-2005.