Papillomaviruses: a systematic review

Abstract In the last decades, a group of viruses has received great attention due to its relationship with cancer development and its wide distribution throughout the vertebrates: the papillomaviruses. In this article, we aim to review some of the most relevant reports concerning the use of bovines as an experimental model for studies related to papillomaviruses. Moreover, the obtained data contributes to the development of strategies against the clinical consequences of bovine papillomaviruses (BPV) that have led to drastic hazards to the herds. To overcome the problem, the vaccines that we have been developing involve recombinant DNA technology, aiming at prophylactic and therapeutic procedures. It is important to point out that these strategies can be used as models for innovative procedures against HPV, as this virus is the main causal agent of cervical cancer, the second most fatal cancer in women.

Relação entre a linfopenia e a persistência da papilomatose alimentar em bovinos intoxicados crônica e espontaneamente por samambaia (Pteridium aquilinum) / Relationship between lymphopenia and the persistence of alimentary papillomatosis in cattle chronically and spontaneously poisoned by bracken fern (Pteridium aquilinum)

Papilomavírus bovino tipo 4 (BPV-4) é responsável pelo desenvolvimento de papilomas no trato alimentar superior (TAS) de bovinos. Os passos necessários para o crescimento, o desenvolvimento e a regressão dos papilomas estão intimamente relacionados com o estado imunológico do animal. A ingestão de samambaia (Pteridium aquilinum) tem sido relacionada como o principal fator envolvido na persistência da infecção pelo BPV-4 no TAS. A teoria que estabelece a relação entre papilomatose alimentar e a formação de CCEs sugere a produção de um estado imunossupressivo crônico pela planta, permitindo a persistência dos papilomas no TAS. Os papilomas serviriam então como sítios de desenvolvimento dos CCEs através da interação entre as proteínas do BPV-4 e os carcinógenos da samambaia. O objetivo deste estudo foi avaliar a relação entre a quantidade de linfócitos circulantes e a papilomatose alimentar em casos de intoxicação espontânea crônica por P. aquilinum em bovinos com CCE no TAS. Quarenta bovinos com CCEs no TAS foram avaliados quanto à idade, à intensidade da papilomatose alimentar no TAS e ao leucograma. Três bovinos tinham leucopenia e um apresentava neutrofilia. A média de linfócitos foi de 5.395 (±1.696) na papilomatose leve, 4.560 (±1.561) na moderada e 5.007 (±1.786) na acentuada. Não houve diferença estatisticamente significativa entre o grau de papilomatose, a idade e a quantidade de linfócitos circulantes. Imunossupressão por linfopenia foi um achado esporádico (três casos) neste estudo. Os resultados indicam que a persistência da papilomatose alimentar em casos espontâneos de intoxicação crônica por samambaia em bovinos não tem relação com a quantidade de linfócitos circulantes e que talvez esteja relacionada a outros fatores imunológicos.

Bovine papillomavirus type-4 (BPV-4) is responsible for the development of papillomas in the upper digestive tract (UDT) of cattle. The necessary steps for the development, growth and regression of papillomas are intimately related with the immunological status of the animal. The consumption of bracken fern (Pteridium aquilinum) has been pointed out as the major factor involved in the persistence of BPV-4 infection of the UDT. The theory involving the relationship between alimentary papillomas and the formation of squamous cell carcinomas (SCCs) suggests the persistence of alimentary papillomatosis through a chronic immunosupressive lymphopenic state induced by bracken fern. The papillomas would serve then as a development site of SCCs through the interaction of BPV-4 oncoproteins and bracken carcinogens. The objective of this study was to evaluate the relationship between lymphopenia and alimentary papillomatosis in spontaneous cases of chronic bracken fern poisoning of cattle. The age, intensity of papillomatosis and the leukon were evaluated of 40 cattle with SCCs of the UDT. Three animals had leukopenia and one had neutrophilia. The mean lymphocyte count (and standart deviation) of mild, moderate and severe papillomatosis was 5,395(±1,696)/mm³, 4,560(±1,561)/mm³ and 5,007(±1,786)/mm³, respectively. There were no statistically significant differences between the intensity of alimentary papillomasis, age and the lymphocyte count. Immunosupression by lymphopenia was a sporadic finding (three cases) in the present study. The results demonstrate that the persistence of alimentary papilomatosis in spontaneous cases of bracken fern-related SCCs of the UDT is not related to lymphopenia and it may be related to other immunological factors.

Sarcoide equino associado ao papilomavírus bovino BR-UEL-4 / Equine sarcoid associated with bovine papillomavirus BR-UEL-4

Um equino, sem raça definida, macho com três anos de idade apresentou múltiplos nódulos na pele, em diversas regiões do corpo. As lesões localizavam-se predominantemente nos lábios, nas bochechas, na região submandibular e na região inguinal direita. Os tumores caracterizavam-se como sarcoides dos tipos misto, fibroblástico, verrucoso e oculto. Histologicamente apresentaram proliferação de fibroblastos dérmicos, muitas vezes ulcerado, com ou sem hiperplasia pseudoepiteliomatosa da epiderme e formação de pequenos grupos isolados de fibroblastos neoplásicos na derme superficial. Três amostras de tecido foram submetidas à extração de DNA e amplificação por PCR com oligonucleotídeos iniciadores genéricos direcionados para uma região interna do gene L1 dos papilomavírus. Os produtos resultantes da amplificação de duas amostras foram sequenciados e demonstraram identidade de 99 por cento com o papilomavírus bovino (BPV) BR-UEL-4. Essa é a primeira descrição da infecção de equinos, bem como de sua associação com sarcoide pelo BPV BR-UEL-4, um suposto novo tipo de BPV identificado recentemente no Brasil a partir de papilomas cutâneos em bovinos.

A 3-year-old, mixed breed, male horse showed multiple nodules in different areas of the skin. Lesions occurred predominantly on the lips, cheeks, and submandibular and right inguinal regions. The nodules were characterized as mixed, fibroblastic, verrucous and occult types of sarcoid. Histologically there was proliferation of dermal fibroblasts, with or without pseudoepitheliomatous hyperplasia of the epidermis (frequently ulcerated), and formation of small isolated groups of neoplastic fibroblasts in the superficial dermis. Three tissue samples were submitted to DNA extraction and PCR amplification with generic primers for the internal region of the papillomavirus L1 gene. The amplified products from two samples were sequenced and showed 99 percent identity with the bovine papillomavirus (BPV) BR-UEL-4. This is the first description of BPV BR-UEL-4 infecting a horse and causing sarcoid in this species. BPV BR-UEL-4 is a putative new BPV type recently identified in skin papillomas in a Brazilian cattle herd.

Identification of the recently described new type of bovine papillomavirus (BPV-8) in a Brazilian beef cattle herd: [revision] / Identificação do novo tipo de papilomavírus bovino (BPV-8) recentemente descrito num rebanho bovino no Brasil: [revisão]

Bovine papillomavirus type 8 (BPV-8) was first detected and described in teat warts as well as in healthy teat skin from cattle raised in Japan. The entire viral genome was sequenced in 2007. Additionally, a variant of BPV-8, BPV-8-EB, was also identified from papillomatous lesions of a European bison in Slovakia. In Brazil, despite the relatively common occurrence of BPV infections, the identification and determination of viral types present in cattle is still sporadic. The aim of this study is to report the occurrence of the recently described BPV-8 in Brazil. The virus was identified in a skin warts obtained from a beef cattle herd located in Parana state, southern Brazil. The papilloma had a macular, non-verrucous gross aspect and was located on the dorsal thorax of a cow. Polymerase chain reaction (PCR) was performed using generic primers for partial amplification of L1 gene. The obtained amplicon (480bp) was cloned and two selected clones were sequenced. The nucleotide sequence was compared to existing papillomaviral genomic sequences, identifying the virus as BPV type 8. This study represents the first report of BPV-8 occurrence in Brazil, what suggests its presence among Brazilian cattle.

A primeira descrição do papilomavírus bovino tipo 8 (BPV-8) foi realizada em amostras de papilomas de teto e de pele saudável de tetos de bovinos no Japão. Em 2007, a seqüência genômica completa do BPV-8 foi determinada. Ainda em 2007, uma variante do BPV-8 (BPV-8-EB) foi identificada em lesões papilomatosas de um bisão europeu na Eslováquia. No Brasil, apesar da infecção pelo BPV ser comumente observada em bovinos, a determinação dos tipos virais associados com a infecção ainda é esporádica. Este estudo tem o objetivo de relatar a ocorrência do BPV-8 no país. A amostra clínica foi obtida em um rebanho de corte do estado do Paraná, região sul do Brasil. O papiloma cutâneo, de aspecto macular e não-verrucoso, estava localizado na região dorsal torácica do animal. A identificação do vírus foi realizada pela reação em cadeia da polimerase (PCR) utilizando primers genéricos para a amplificação parcial do gene L1. O produto amplificado, com aproximadamente 480 pb, foi clonado e os fragmentos presentes em dois clones foram seqüenciados. A comparação da seqüência de nucleotídeos com a de outros papilomavírus demonstrou 100 por cento de identidade com o BPV-8. Assim, esta é a primeira descrição da ocorrência do BPV-8 no Brasil, o que sugere a sua presença nos rebanhos bovinos brasileiros.

Bovine papillomavirus type 4 L1 gene transfection in a Drosophila S2 cell expression system: absence of L1 protein expression

The development of a bovine papillomavirus (BPV) vaccine is an outstanding challenge. BPV protein L1 gene transfection in the Drosophila melanogaster S2 cell expression system failed to produce L1 protein notwithstanding correct L1 gene insertion. Severe genetic inbalance in the host cell line, including cytogenetic alterations, may account for the lack of protein expression.

O desenvolvimento de uma vacina para papilomavirus bovino (BPV) consiste em grande desafio. A transfecção do gene codificante da proteína L1 de BPV em sistema de células S2 de Drosophila melanogaster não logrou sucesso, apesar da correta inserção da seqüência gênica em vetor apropriado.Graves alterações genéticas na linhagem celular S2, que incluem aberrações cromossômicas, provavelmente estão relacionadas à ausência da expressão da proteína desejada.

Simultaneous presence of bovine papillomavirus and bovine leukemia virus in different bovine tissues: in situ hybridization and cytogenetic analysis

Bovine papillomavirus (BPV) DNA sequences were detected in different tissues, in addition to epithelium. Cytogenetic abnormalities were observed in blood lymphocytes. The presence of more than one virus in a single tissue is a difficult aspect to evaluate, especially when the DNA sequences are detected in tissues that are not specifically targeted by the virus. BPV and bovine leukemia virus (BLV) are clastogenic, causing chromosome aberrations in peripheral blood lymphocytes. In the present study, we investigated the simultaneous presence of DNA sequences of both viruses and the possibility of vertical transmission and compared the types of chromosome aberrations related to viral action. BPV 1, 2, and 4 DNA sequences were found in three females of the herd and in their offspring. BLV DNA sequences were not detected in their progeny. A newborn calf that was negative for BLV infection showed specific chromosome rearrangements possibly related to the effect of infection with BPV.

PapillomatosIs in cattle: in situ detection of bovine papillomavirus DNA sequences in reproductive tissues

Bovine papillomatosis is a common viral infection in Brazil that is caused by a bovine papillomavirus(BPV). Dissemination is by direct contact between infected animals, although the investigation of othermodes of transmission is a very important aspect in the management of this condition. BPV DNA sequenceshave been detected in many tissues by using the polymerase chain reaction. In this work, we used in situhybridization to detect BPV DNA sequences in bovine reproductive tissues and cells. The detection ofBPV in these tissues strongly suggests that these sequences could be an important alternative of viraltransmission that could contribute to the widespread incidence of bovine papillomatosis and its complexpathology. Alternatively, the viral sequences could result from cell apoptosis and may therefore not bedirectly involved in the infection.