Bovine papillomavirus type 2 from bovine cutaneous papillomas in Australia

SUMMARY Papillomavirus DNA was demonstrated in 10 of 12 samples extracted from cutaneous bovine papillomas and electrophoresed on agarose gels without further treatment or after concentration by freeze drying. Six of the DNA samples were treated with restriction endonucleases and 4 had restriction patterns characteristic of bovine papillomavirus type 2.     

Induction of virus-producing tumours in athymic nude mice by bovine papillomavirus type 4

Bovine papillomavirus type 4 (BPV-4), the causative agent of alimentary papillomatosis, has been used to infect, in vitro, fragments of palatine mucosa from late term bovine fetuses. These small explants were placed beneath the renal capsule of athymic nude mice where they grew to produce, at first, squamous epithelial cysts containing BPV-4 genomic DNA and, later, papillomas which were morphologically identical to those of cattle and which contained large amounts of replicating virus. The possible utility of this technique in assessing neutralising antibodies in vaccine development is discussed.     

Bovine papillomavirus infection in equine sarcoids and in bovine bladder cancers

Bovine papillomavirus (BPV) type 2 is involved in carcinogenesis of the urinary bladder in cattle, while BPV-1 is commonly associated with equine sarcoid tumours. In both cases the early viral proteins are expressed, but virion is not produced. Given the similarities in BPV biology between the tumours in cattle and horses, bovine bladder cancers and equine sarcoids were compared with respect to physical status, load of viral DNA and variability of the E5 open reading frame (ORF). Rolling circle amplification demonstrated that BPV-1 and BPV-2 genomes exist as double stranded, episomal, circular forms in the two tumours. Realtime quantitative PCR revealed that equine sarcoids contained higher viral DNA loads compared to bovine bladder cancers. The BPV-1 E5 ORF showed sequence variation but BPV-2 ORF did not. The presence of BPV-1 E5 variations or their absence in the BPV-2 E5 ORF does not appear to have an effect on viral DNA load in either tumour type.     

Bovine herpesvirus type 4: a special herpesvirus (review article)

This paper summarizes the history of and information on bovine herpesvirus type 4 (BoHV-4) from the first isolation to the most recent results. For almost twenty years BoHV-4 has been considered a typical herpes 'orphan' virus, which infects several species but causes no illness. The latest experiments revealed the close relationship of this virus with the immune system and other tissues. The virus was even considered as a possible candidate for a vector vaccine. BoHV-4 as a strange herpesvirus has several features which are not characteristic of other herpesviruses, such as several latency sites, persistence in serum, dividing cells necessary for virus replication, and the wide host range. In addition to describing the main features of the virion, replication, clinical signs, nomenclature problems, this review intends to concentrate on the new and strange results coming out from several laboratories worldwide. It is also suggested that because the virus combines several properties of various herpesvirus subfamilies and because of its close relationship with the immune system, it may deserve further attention as a representative of a potentially new genus within the Gammaherpesvirinae subfamily.     

Linear B-cell epitopes in the N-terminus of L2 of bovine papillomavirus type 4

The minor capsid protein L2 of bovine papillomavirus type 4 (bpv-4) is a very effective prophylactic vaccine which induces the production of virus neutralising antibodies and prevents virus-induced papillomatosis. The virus neutralising activity resides in the first 200 N-terminal amino acids of L2 (L2a). To further investigate the humoral immune response to L2, and the role it plays during infection and in prophylactic vaccination, the presentation of B-cell linear epitopes of L2a has been analysed in calves infected with the virus but not vaccinated, and in calves vaccinated with virus, L2a or E7. Several B-cell epitopes have been identified in L2a by the use of overlapping peptides; the epitopes varied in the different groups of animals, indicating that the epitopes presented by denatured L2 are not presented by the virus, and that therefore, although responsible for L2 vaccine-induced immunity, they may play little role in naturally acquired immunity.     

澳大利亚牛结核病的根除及参考意义

自1970年起,澳大利亚历时31年成功消灭了牛结核病。本文介绍了该病得以根除的几大要素,包括行业和政府支持、法律法规完善、根除方案详尽、根除资金保障、技术标准统一、屠宰场监测到位、追踪溯源和严格控制动物移动等,阐述了澳大利亚为根除该病采取的检测方法、牛标识系统、无疫群的建立与确认等具体措施,分析了其做法对我国结核病防控的借鉴意义。     

Bovine papillomavirus DNA can be detected in keratinocytes of equine sarcoid tumors

Bovine papillomavirus (BPV)-1 and -2 is linked to equine sarcoids, a commonly observed skin tumor in horses that is of considerable veterinary importance. Previous studies using in situ hybridization have detected BPV DNA only in fibroblasts and not in keratinocytes of sarcoids. In contrast, normal equine skin latently infected with BPV shows a dysplastic epithelium without dermal changes, similar to lesions induced by other papillomavirus types infecting the epithelium. The first goal of our study was to describe the epidermal and dermal characteristics of several stages in sarcoid development. Next, we explored whether BPV can infect epidermal cells in the horse using real-time PCR on laser-micro-dissected keratinocytes and fibroblasts. We found that latently infected normal skin samples and a subset of early stage sarcoids show dysplastic, koilocyte-like epithelial changes. BPV DNA was detected in keratinocytes in 40% of the samples with these particular epithelial properties, whereas advanced sarcoids only had BPV DNA in the fibroblasts. These data may indicate a novel and intriguing pathway of BPV infection in the horse composed of a first step of keratinocyte infection, followed by migration of viral material towards the dermis resulting in infection of sub-epidermal fibroblasts and their fully transformed phenotype. Additionally, an example of co-existence of a dermal BPV-1 and an epidermal BPV-2 infection in the same lesion is shown, indicating that horses can harbor infection with more than one BPV type at the same time.     

牛疱疹病毒4研究进展

国外早已对牛疱疹病毒4(BHV-4)做了广泛的研究,尤其是作为有潜力的病毒载体,它更是引起了诸多学者的兴趣,但国内尚未见对该病毒的深入研究.为了更加全面地认识该病毒,论文对BHV-4基本生物学、分子生物学特征及流行病学等方面做了较为全面的综述,以期对相关研究提供资料.     

Bovine adenovirus type 3 pneumonia in dexamethasone-treated calves

The effects of immunosuppression were examined in 1.5-month-old calves that were given dexamethasone (DM) before endobronchial inoculation with bovine adenovirus type 3 (BAV-3). Immunohistopathologically, severe necrotizing bronchiolitis with eosinophilic and basophilic intranuclear inclusion bodies was observed both in DM-treated 1.5-month-old infected calves and in non-DM-treated 7-day-old infected calves. These inclusion bodies were correlated with the detection of BAV-3 antigen and viral particles. The presence of inclusion bodies in the desquamated epithelial cells or of BAV-3 antigen, or both, correlated well with the isolated level of BAV-3 in bronchoalveolar lavage (BAL) fluid. Few immunoglobulin (IgG, IgM, and IgA)-containing B lymphocytes or CD8+ T lymphocytes infiltrated the pneumonic lesion in both the 7-day-old and the DM-treated 1.5-month-old infected calves. Thus, depletion of CD8+ T lymphocytes in calves might influence the clearance of BAV-3 from respiratory tissues.     

Bovine papillomavirus E5 oncoprotein upregulates parkin-dependent mitophagy in urothelial cells of cattle with spontaneous papillomavirus infection: A mechanistic study

This study aimed to provide mechanistic insights into mitophagy pathway associated with papillomavirus infection in urothelial cells of cattle. The elimination of mitochondria via autophagy, termed mitophagy, is an evolutionarily conserved mechanism for mitochondrial quality control and homeostasis. PINK1/parkin-mediated mitophagy, a ubiquitin-dependent selective autophagy of dysfunctional mitochondria, has been described here, for the first time, in urothelial cells from 25 bladder cancers in cattle infected by bovine papillomavirus (BPV). The expression of BPV-2 and BPV-13 E5 oncoprotein was detected by RT-PCR. Abnormal mitochondria delimited by expanding phagophores, were peculiar ultrastructural features of neoplastic urothelial cells. High levels of mitochondrial phosphorylated PINK1/parkin were observed in neoplastic urothelial cells infected by BPVs. Phosphoparkin interacted with mitofusin 2 (Mfn2) and ubiquitin (Ub), which confirmed that Mfn2 is a parkin receptor at the mitochondrial level, where parkin interacted also with Ub. Furthermore, parkin established a complex that was comprised of optineurin, p62, LC3, laforin, and embryonic stem cell-expressed Ras (ERAS), that interacted with BPV E5 oncoprotein, and Bag3, which, in turn, regulated the formation of a complex composed of Hpc70/Hsp70, CHIP, an HSC70-interacting E3 ubiquitin ligase. It is conceivable that ERAS is involved in mitophagosome maturation via phosphatidylinositol 3-kinase (PI3K) pathway. Bag3, in association with Hsc70/Hsp70, may contribute to the transport and degradation of CHIP-ubiquitinated cargo as this complex recognises ubiquitinated cargos and transports them to aggresomes to be degraded. Furthermore, Bag3 may be involved in mitophagosome formation as it interacted with synaptopodin 2, which is known to play a role in mitophagosome biogenesis.     

Interaction of a Green Recombinant Bovine Herpesvirus 4 with In Vitro-produced Bovine Embryos

The objective of the present study was to assess whether bovine herpesvirus 4 (BHV-4) is able to infect in vitro-produced bovine embryos. A green recombinant BHV-4 (BHV-4EGFPTK), obtained by insertion of an EGFP gene into the TK locus of BHV-4, was used. The presence of this marker protein made it possible easily to detect infected cells under physiological conditions, without harmful manipulation of the cells or the addition of exogenous substrates, so that the spread of the virus could be followed in real time. Zona pellucida intact (ZP-I) and zona pellucida open (ZP-O) blastocytes were exposed to 10⁶ TCID₅₀ viral particles and infection was monitored by fluorescent microscopy for 48 h. Expression of EGFP and degeneration of embryonic cells was observed in three of the 18 ZP-O embryos, but in none of the ZP-I embryos. It was concluded from this preliminary study that BHV-4 has only a low ability to infect in vitro-produced bovine embryos, depending on the absence of ZP, the amount of virus present and the stage of embryonic development. However, embryonic stem cells could be transduced by BHV-4EGFPTK just after differentiation, as shown by expression of EGFP.     

Bovine viral diarrhea virus type 2-induced meningoencephalitis in a heifer

The brain from a 15-month-old, black female Angus, with a 48-hour history of central nervous system disease, was submitted to the Oklahoma Animal Disease Diagnostic Laboratory. Microscopic findings consisted of acute, multifocal meningoencephalitis, with neuronal degeneration and necrosis and gliosis. Viral isolation yielded noncytopathic bovine viral diarrhea virus (BVDV). Virus genotyping classified the virus as BVDV type 2. Immunohistochemical labeling for BVDV antigens with BVD MAb 3.12F1 clone was prominent in the cytoplasm of neurons, glial cells, ependymal epithelium, perivascular macrophages and spindle cells, smooth muscle cells, and intravascular monocytes of the cerebrum and brain stem. Laboratory results support that tissue alterations occurred as a result of BVDV type 2 infection. In the absence of other clinical signs related to BVDV infection and using the microscopic and laboratory evidence presented, we propose that the BVDV type 2 isolated from this case may represent a neurovirulent strain of the virus. To the best of our knowledge, this is the first report of brain lesions and neuronal viral antigen localization in BVDV genotype 2 viral infection, acquired either congenitally or postnatally.