Isolation of a Divergent Strain of Bovine Parainfluenza Virus Type 3 (BPIV3) Infecting Cattle in China

Prevalence, Molecular Characteristics and Virulence Identification of Bovine Parainfluenza Virus Type 3 in China

Bovine parainfluenza virus type 3 (BPIV-3) is one of the major pathogens of the bovine respiratory disease complex (BRDC). BPIV-3 surveillance in China has been quite limited. In this study, we used PCR to test 302 cattle in China, and found that the positive rate was 4.64% and the herd-level positive rate was 13.16%. Six BPIV-3C strains were isolated and confirmed by electron microscopy, and their titers were determined. Three were sequenced by next-generation sequencing (NGS). Phylogenetic analyses showed that all isolates were most closely related to strain NX49 from Ningxia; the genetic diversity of genotype C strains was lower than strains of genotypes A and B; the HN, P, and N genes were more suitable for genotyping and evolutionary analyses of BPIV-3. Protein variation analyses showed that all isolates had mutations at amino acid sites in the proteins HN, M, F, and L. Genetic recombination analyses provided evidence for homologous recombination of BPIV-3 of bovine origin. The virulence experiment indicated that strain Hubei-03 had the highest pathogenicity and could be used as a vaccine candidate. These findings apply an important basis for the precise control of BPIV-3 in China.

Isolation and Genomic Characterization of a Chinese Genotype C Bovine Parainfluenza Virus Type 3 from Cattle and Its Pathogenicity in C57BL/6 Mice

Bovine parainfluenza virus type 3 (BPIV-3), also known as bovine respirovirus 3, is a common respiratory pathogen associated with bovine respiratory disease (BRD). BPIV-3 has currently circulated worldwide; however, data on the prevalence and genetic characteristics of BPIV-3 are still scarce and limited. In this study, the BPIV-3 strain SC was identified and isolated from cattle presenting with clinical signs of BRD in China. Animal experiments indicated that BPIV-3 SC can successfully infect C57BL/6 mice and induce weight loss, lung inflammatory cell infiltration, and inflammatory cytokine expression in mice. In addition, the complete genome of BPIV-3 SC was obtained using next-generation sequencing and was 15,473 bp in length. Phylogenetic analysis indicated that BPIV-3 SC belonged to genotype C, which clustered in the same large clade consisting of a population of Chinese genotype C strains but was found to be different from the other strains upon further differentiation. Compared to other Chinese genotype C strains, the BPIV-3 SC showed 70 unique nucleotide mutations and 13 unique amino acid mutations in the HN, P, and L proteins, suggesting a unique genetic evolution of BPIV-3 SC. In conclusion, we isolated and characterized a differential Chinese genotype C BPIV-3, which contributed to an understanding of the prevalence and evolution of BPIV-3 in China.

Immunogenicity and protective efficacy of a recombinant adenovirus containing the fusion protein of bovine parainfluenza virus type 3 genotype C in mice

Bovine parainfluenza virus type 3 (BPIV3) is a viral respiratory pathogen of cattle that causes substantial economic losses. A replicating-defective recombinant human adenovirus type 5 (HAd5), carrying a fusion protein of BPIV3 genotype C (HAd5-F), was constructed and evaluated for its immunogenicity and protective efficacy in mice. After intramuscular injection with the HAd5-F, the IgG titers against F proteins increased to 1:102,400, and virus-neutralizing titers increased to 1:256, significantly higher than those in the group injected with inactivated BPIV3C in mice (p<0.05). The splenic CD4+/CD8+T lymphocytes and IFN-γ+/IL-4+ cytokine percentages were more significant in the HAd5-F group than those in the control group. A BPIV3C challenge in a mouse model was used to assess protective efficacy of the HAd5-F. The viral loads in the lungs and tracheas of mice immunized with the HAd5-F were significantly lower than those in the control group (p<0.0001). There were no significant histopathological alterations in the lungs of mice vaccinated with the HAd5-F. These findings suggested that the HAd5-F elicited excellent immunity against BPIV3C infection.

Bovine Airway Models: Approaches for Investigating Bovine Respiratory Disease

Bovine respiratory disease (BRD) is a multifactorial condition where different genera of bacteria, such as Mannheimia haemolytica, Histophilus somni, Pasteurella multocida, and Mycoplasma bovis, and viruses, like bovine respiratory syncytial virus, bovine viral diarrhea virus, and bovine herpes virus-1, infect the lower respiratory tract of cattle. These pathogens can co-infect cells in the respiratory system, thereby making specific treatment very difficult. Currently, the most common models for studying BRD include a submerged tissue culture (STC), where monolayers of epithelial cells are typically covered either in cellular or spent biofilm culture medium. Another model is an air-liquid interface (ALI), where epithelial cells are exposed on their apical side and allowed to differentiate. However, limited work has been reported on the study of three-dimensional (3D) bovine models that incorporate multiple cell types to represent the architecture of the respiratory tract. The roles of different defense mechanisms in an infected bovine respiratory system, such as mucin production, tight junction barriers, and the production of antimicrobial peptides in in vitro cultures require further investigation in order to provide a comprehensive understanding of the disease pathogenesis. In this report, we describe the different aspects of BRD, including the most implicated pathogens and the respiratory tract, which are important to incorporate in disease models assembled in vitro. Although current advancements of bovine respiratory cultures have led to knowledge of the disease, 3D multicellular organoids that better recapitulate the in vivo environment exhibit potential for future investigations.

Isolation and Molecular Characterisation of Respirovirus 3 in Wild Boar

Paramyxoviruses are important pathogens affecting various animals, including humans. In this study, we identified a paramyxovirus in 2004 (180608_2004), isolated from a sample of the femoral marrow bone of a wild boar carcass imported from Australia. Antigenic and morphological characteristics indicated that this virus was similar to members of the family Paramyxoviridae. The complete genome phylogenetic analysis grouped this virus into genotype A of bovine parainfluenza virus type 3 (BPIV-3), recently renamed bovine respirovirus type 3 (BRV3), which also includes two swine paramyxoviruses (SPMV)-Texas-81 and ISU-92-isolated from encephalitic pigs in the United States in 1982 and 1992, respectively. The wild boar 180608_2004 strain was more closely related to both the BRV3 shipping fever (SF) strain and the SPMV Texas-81 strain at the nucleotide and amino acid levels than the SPMV ISU-92 strain. The high sequence identity to BRV3 suggested that this virus can be transferred from cattle to wild boars. The potential for cross-species transmission in the Respirovirus genus makes it essential for intensified genomic surveillance.

Discovery and characterization of novel paramyxoviruses from bat samples in China

Many paramyxoviruses are responsible for a variety of mild to severe human and animal diseases. Based on the novel discoveries over the past several decades, the family Paramyxoviridae infecting various hosts across the world includes 4 subfamilies, 17 classified genera and 78 species now. However, no systematic surveys of bat paramyxoviruses are available from the Chinese mainland. In this study, 13,064 samples from 54 bat species were collected and a comprehensive paramyxovirus survey was conducted. We obtained 94 new genome sequences distributed across paramyxoviruses from 22 bat species in seven provinces. Bayesian phylodynamic and phylogenetic analyses showed that there were four different lineages in the Jeilongvirus genus. Based on available data, results of host and region switches showed that the bat colony was partial to interior, whereas the rodent colony was exported, and the felines and hedgehogs were most likely the intermediate hosts from Scotophilus spp. rather than rodents. Based on the evolutionary trend, genus Jeilongvirus may have originated from Mus spp. in Australia, then transmitted to bats and rodents in Africa, Asia and Europe, and finally to bats and rodents in America.

Isolation, Identification, and Genetic Phylogenetic Analysis of Two Different Genotypes of Bovine Parainfluenza 3 Virus in China

Bovine parainfluenza virus 3 (BPIV3) is one of several viruses that contribute to bovine respiratory disease complex (BRDC). During this study, isolation of BPIV3 was attempted from 20 PCR-positive swabs by Madin-Darby Bovine Kidney (MDBK) cells. Nine samples showed obvious cytopathic lesions identified as BPIV3 by reverse-transcription polymerase chain reaction amplification and sequencing. The genomes of isolates XJ21032-1 and XJ20055-3 were sequenced using Illumina sequencing technology and determined to have lengths of 15,512 bp and 15,479 bp, respectively. Phylogenetic analysis revealed that isolate XJ21032-1 was genotype B, and isolate XJ20055-3 was genotype C. In addition, the two isolates had multiple amino acid changes in nucleocapsid protein, fusion protein, and hemagglutinin/neuraminidase, major antigenic proteins. This allows the further recognition of the presence of BPIV3 type B in Chinese cattle herds. We hope this will help trace the origin of BPIV3, improve the understanding of differences between genotypes, and provide data support for vaccine development.

First Isolation and Characteristics of Bovine Parainfluenza Virus Type 3 from Yaks

The yaks belong to the genus Bos within the family Bovidae that live in the Tibet Plateau and is an indispensable economic resource for the local herders. Respiratory tract infections are common diseases in yaks caused by various pathogens; however, there have been no reports of bovine parainfluenza virus type 3 (BPIV3) infection. This study was conducted to investigate the pathogens and analyze their characteristics from the four yak lung samples with severe respiratory tract infection symptoms in the yak farm. Results showed that out of four lung samples, three were identified as BPIV3-positive by RT-PCR. A BPIV3 strain (10^6.5 TCID₅₀/mL) was successfully isolated from the BPIV3-positive lung samples using Madin–Darby bovine kidney cells. The isolate caused systemic infection in the BALB/c mice and induced pathological changes in the lungs. Moreover, three complete BPIV3 genomes were amplified from the clinical samples. Phylogenetic trees based on the complete genomes, hemagglutinin-neuraminidase protein (HN), phosphoprotein (P), and large polymerase subunit protein (L) amino acid sequences showed that the complete BPIV3 genomes belonged to BPIV3 genotype C, and clustered into a large branch with the Chinese strains, although the three yak BPIV3 strains were clustered into a small branch. Compared to known BPIV3 genotype C strains in GenBank, the three genomes of yak BPIV3 showed four identical amino acid mutations in the HN, P and L proteins, suggesting a unique genetic evolution of BPIV3 in yaks. This study first isolated and characterized the BPIV3 from yaks, which contributed to the understanding of the infection and evolution of BPIV3 in yaks in the Tibet Plateau.

Manipulating adrenergic stress receptor signalling to enhance immunosuppression and prolong survival of vascularized composite tissue transplants

BACKGROUND

Vascularized composite tissue allotransplantation (VCA) to replace limbs or faces damaged beyond repair is now possible. The resulting clear benefit to quality of life is a compelling reason to attempt this complex procedure. Unfortunately, the high doses of immunosuppressive drugs required to protect this type of allograft result in significant morbidity and mortality giving rise to ethical concerns about performing this surgery in patients with non-life-threatening conditions. Here we tested whether we could suppress anti-graft immune activity by using a safe β2 -adrenergic receptor (AR) agonist, terbutaline, to mimic the natural immune suppression generated by nervous system-induced signalling through AR.

METHODS

A heterotopic hind limb transplantation model was used with C57BL/6 (H-2b) as recipients and BALB/c (H-2d) mice as donors. To test the modulation of the immune response, graft survival was investigated after daily intraperitoneal injection of β2 -AR agonist with and without tacrolimus. Analyses of immune compositions and quantification of pro-inflammatory cytokines were performed to gauge functional immunomodulation. The contributions to allograft survival of β2 -AR signalling in donor and recipient tissue were investigated with β2 -AR-/- strains.

RESULTS

Treatment with the β2 -AR agonist delayed VCA rejection, even with a subtherapeutic dose of tacrolimus. β2 -AR agonist decreased T-cell infiltration into the transplanted grafts and decreased memory T-cell populations in recipient's circulation. In addition, decreased levels of inflammatory cytokines (IFN-γ, IL-6, TNF-α, CXCL-1/10 and CCL3/4/5/7) were detected following β2 -AR agonist treatment, and there was a decreased expression of ICAM-1 and vascular cell adhesion molecule-1 in donor stromal cells.

CONCLUSIONS

β2 -AR agonist can be used safely to mimic the natural suppression of immune responses, which occurs during adrenergic stress-signalling and thereby can be used in combination regimens to reduce the dose needed of toxic immunosuppressive drugs such as tacrolimus. This strategy can be further evaluated for feasibility in the clinic.

A lateral flow dipstick combined with reverse transcription recombinase polymerase amplification for rapid and visual detection of the BVDV and BPIV3

Bovine respiratory disease complex (BRDC) is a serious disease affecting feedlot cattle in China and likely other places worldwide. Bovine viral diarrhea virus (BVDV) and bovine parainfluenza virus type 3 (BPIV3) are principally responsible for causing BRDC, and are a major strain to the industrial economy. Eradication of these viruses/disease requires swift viral identification and treatment. Hence, this study established a fast and easy procedure of BVDV and BPIV3 identification that employs reverse transcription recombinase polymerase amplification (RT-RPA) and lateral flow dipstick (LFD), and uses primers and lateral flow (LF) probe targeting the 5'-UTR gene of BVDV and phosphoprotein P gene of BPIV3, respectively. Our assay was able to successfully amplify BVDV and BPIV3 RNA within 25 min at 35 °C using RT-RPA, with products visible on the LFD within 5 min at room temperature (RT). The lowest detection limits were 50 RNA molecules for BVDV and 34 RNA molecules for BPIV3 per reaction. We also demonstrated that the established dual RT-RPA LFD assay was precise and targeted, harboring excellent potential to become an onsite molecular diagnostic tool in the detection of BVDV and BPIV3. This method can detect BVDV (Pestivirus A, B) and BPIV3, and exhibit no cross-reaction with other viruses like the classical swine fever virus (CSFV) and infectious bovine rhinotracheitis virus (IBRV). The assay performance was further assessed with clinical samples, and demonstrated good performance in comparison to real-time RT-PCR (RT-qPCR). Moreover, the RT-RPA LFD assay was comparitively rapid and required minimal training.

Entry of bovine parainfluenza virus type 3 into MDBK cells occurs via clathrin-mediated endocytosis and macropinocytosis in a acid-dependent manner

Bovine parainfluenza virus 3 (BPIV3) is an important respiratory pathogen of both young and adult cattle. No specific therapies are available for BPIV3. Understanding the viral internalization pathway of BPIV3 will provide new strategies for the development of antiviral treatments. Here, the entry mechanism of BPIV3 into MDBK cells was analyzed using chemical inhibitors and RNA silencing. Our data demonstrated that treatment with an inhibitor targeting the clathrin-mediated pathway or clathrin heavy chain (CHC) knockdown suppressed the entry of BPIV3 into MDBK cells. In contrast, sequestration of cellular cholesterol by nystatin or silencing of caveolin-1 had no effect on viral entry. Moreover, inhibition of critical modulators of macropinocytosis significantly reduced BPIV3 uptake. In addition, fluid-phase uptake was significantly increased in cells infected with BPIV3, which is indicative of virus-induced facilitation of macropinocytosis. These results suggest that BPIV3 enters MDBK cells via macropinocytosis and clathrin- but not caveolar-dependent endocytosis. Furthermore, inhibition of endosomal acidification and activation of cathepsin blocked BPIV3 entry, demonstrating that BPIV3 entered MDBK cells in a acid-dependent manner and required cathepsin L. Finally, we demonstrated that macropinocytosis but not clathrin-mediated endocytosis is dependent on actin dynamics during BPIV3 infection.

Bovine Parainfluenza Virus Type 3 (BPIV3) Enters HeLa Cells via Clathrin-Mediated Endocytosis in a Cholesterol- and Dynamin-Dependent Manner

Bovine parainfluenza virus 3 (BPIV3) is a crucial causative agent of respiratory disease in young and adult cattle. No specific therapies are available for BPIV3 infection. Understanding the internalization pathway of the virus will provide a new strategy for the development of antiviral therapy. Here, the mechanism of BPIV3 entry into HeLa cells was analyzed using RNA silencing and pharmacological inhibitors. Treatment of HeLa cells with hypertonic medium prevented BPIV3 internalization. These results indicated that BPIV3 entered HeLa cells via receptor-mediated endocytosis. Moreover, removing cell membrane cholesterol through MβCD treatment hampered viral penetration but not viral replication. In addition, BPIV3 infection was inhibited by pretreatment with dynasore or chlorpromazine (CPZ) or knockdown of dynamin II or clathrin heavy chain. However, virus entry was unaffected by nystatin, EIPA, wortmannin, or cytochalasin D treatment or caveolin-1 knockdown. These data demonstrated that the entry of BPIV3 into HeLa cells was dependent on clathrin-mediated endocytosis but not on caveolae-mediated endocytosis or the macropinocytosis pathway. Many viruses are transported to endosomes, which provide an acidic environment and release their genome upon separation from primary endocytic vesicles. However, we found that BPIV3 infection required endosomal cathepsins, but not a low pH. In summary, we show, for the first time, that BPIV3 enters HeLa cells through the clathrin-mediated endocytosis pathway, presenting novel insights into the invasion mechanism of Paramyxoviridae.