Investigação do caráter zoonótico do vírus da leucose bovina

O câncer de mama é uma patologia que causa risco de vida e é um grande problema de saúde pública em todo mundo. No Brasil, o câncer de mama é responsável por quase 1/3 de todos os cânceres diagnosticados em mulheres e são necessários mais estudos para compreender melhor a etiopatogenia, profilaxia e novos tratamentos dessa doença mortal. Recentemente, vários estudos levantaram a possibilidade de que um retrovírus animal, o vírus da leucose bovina (BLV), causador da leucose enzoótica bovina (EBL), pudesse estar relacionado ao câncer de mama em mulheres. O BLV causa uma infecção silenciosa e geralmente negligenciada que, em alguns animais, evolui para linfocitose persistente e, por fim, para linfoma de células B. O vírus está disseminado na pecuária leiteira e o consumo de laticínios e de carne bovina é maior no Sul do Brasil, onde o estudo foi realizado, em comparação com outras regiões do país. O Capítulo 1 aborda a detecção de diferentes genes de BLV em tecido mamário de mulheres (saudáveis e com câncer) e de bovinos com EBL, e a comparação das sequências de nucleotídeos. É observado que eles são muito semelhantes, com uma identidade de nucleotídeos variando de 97,8 a 99,7% e que pertencem ao genótipo 1. Esse é o primeiro relato da presença do gene env de BLV em humanos. A detecção do provirus de BLV através de PCR se mostrou uma técnica eficaz, reforçando ainda mais a hipótese recente de que o BLV é um agente zoonótico, ampliando o conhecimento atual sobre a gama de hospedeiros do vírus. O Capítulo 2 aborda a detecção dos diferentes genes de BLV em tecido mamário fresco e em leucócitos humanos de pacientes com e sem câncer de mama. A análise estatística determinou um cálculo amostral de 218 espécimes. Desses, 25 foram analisados e todas as amostras foram negativas para os genes avaliados. O número pequeno de amostras analisadas pode ser a justificativa pela qual nenhuma amostra foi positiva até o momento. Este trabalho coloca em pauta a relação entre o BLV e o câncer de mama, colocando o vírus como alvo para novos estudos.Breast cancer is a life-threatening pathology and a major burden to public health worldwide. In Brazil, breast cancer accounts for almost 1/3 of all cancer diagnosed in women and more studies focusing on the etiopathogenesis, prophylaxis and novel treatments of this deadly condition are required. Recently, several studies raised the possibility that an animal retrovirus, the bovine leukemia virus (BLV), which causes enzootic bovine leukemia (EBL), could be related to breast cancer in women. BLV causes a silent and usualy neglected infection that in some animals evolves to persistent lymphocytosis and ultimately to B cell lymphoma. The virus is widespread on dairy cattle and the consumption of dairy-derived products and cattle meat is higher in South Brazil, where the study was conducted, compared to other regions of the country. Chapter 1 covers the detection of different BLV genes in breast tissue from women (healthy or with cancer) and from cattle with EBL, and the comparison of nucleotide sequences. It was observed that they are very similar, with a nucleotide identity ranging from 97.8 to 99.7% and belonging to genotype 1. This is the first report of the presence of the BLV env gene in humans. The detection of the BLV provirus through PCR has proven to be an effective technique, further reinforcing the recent hypothesis that BLV is a zoonotic agent, expanding the current knowledge about the host range of the virus. Chapter 2 addresses the detection of different BLV genes in fresh breast tissue and human leukocytes in patients with and without breast cancer. The statistical analysis determined a sample calculation of 218 specimens. Of these, 25 were analyzed and all samples were negative for the evaluated genes. The statistical analysis determined a sample calculation of 218 specimens. Of these, 25 were analyzed and all samples were negative for the evaluated genes. The small number of samples analyzed may be the reason why no sample has been positive so far. This work highlights the relationship between BLV and breast cancer, placing the virus as a target for further studies

Bovine leukemia viral DNA found on human breast tissue is genetically related to the cattle virus

Bovine leukemia virus (BLV) infection is widespread in cattle and associated with B cell lymphoma. In a previousstudy we demonstrated that bovine leukemia viral DNA was detected in human breast tissues and significantly associated with breast cancer. Our current study aimed to determine whether BLV DNA found in humans and cattle at the same geographical region were genetically related. DNA was extracted from the breast tissue of healthy (n = 32) or cancerous women patients (n = 27) and from the blood (n = 30) of cattle naturally infected with BLV, followed by PCR-amplification and partial nucleotide sequencing of the BLV env gene. We found that the nucleotide sequence identity between BLV env gene fragments obtained from human breast tissue and cattle blood ranged from 97.8 to 99.7% and grouped into genotype 1. Thus, our results further support the hypothesis that this virus might cause a zoonotic infection

Characterization of an IgM-like immunoglobulin from silver catfish (Rhamdia quelen) serum and its use for the production of polyclonal antibodies and development of immunoassays

Abstract: Knowledge on fish immunoglobulin (Ig) characteristics and the availability of monoclonal or polyclonal antibodies to fish Igs are essential to evaluate the humoral immune response and the Ig distribution on leukocyte cells. We demonstrated that silver catfish serum Ig is composed of one immunodominant H chain with approximately 75k Da and one L chain with approximately 28 kDa, similar to human IgM. Rabbit polyclonal antibodies to the catfish IgM-like Ig recognized both the H and L chain and were useful in developing an indirect ELISA to measure the production of antibodies in fish immunized with bovine serum albumin. Dot blot and western blot cross-reactivity studies indicated a wide degree of epitope sharing amongst Ig from several Siluriformes and Characiformes fish indigenous to Brazilian rivers. In these fish species, polyclonal antibodies reacted mostly with the H chain. The results presented here are central to the development of tools and strategies to investigate the antibody production to inoculated antigens and tissue distribution of Ig molecules in native fish species. Furthermore, because of the wide range of cross-reactivity, polyclonal antibodies to silver catfish IgM-like Ig might be used to develop immunoassays to measure the humoral immune response in other fish species

Immunomodulatory effects of dietary β-glucan in silver catfish (Rhamdia quelen)

ABSTRACT: The immunomodulatory effects of dietary β-glucan were evaluated in silver catfish. β-glucan was added to the diet (0.01%, and 0.1%) and fed to the fish for 21 days, to evaluate effects on blood and some innate immune parameter, or fed for 42 days, to evaluate growth rate and resistance to challenge with pathogenic Aeromonas hydrophila. We found that adding β-glucan to the diet had no effect on fish growth and no effect on blood cells, or serum bacterial agglutination and serum myeloperoxidase activity. However, fish that received β-glucan in the diet had the natural hemolytic activity of complement significantly higher compared to control fish. Furthermore, fish fed with β-glucan and challenged with A. hydrophila had fewer bacteria in blood and presented a significantly higher survival rate compared to control fish. Thus, we concluded that β-glucan might be explored as feed additive aiming to improve silver catfish innate immunity and resistance to specific pathogen

The virome of the white‑winged vampire bat Diaemus youngi is rich in circular DNA viruses

In the Neotropical region, the white-winged vampire bat (Diaemus youngi) is the rarest of the three species of vampire bats. This bat species feeds preferentially on bird blood, and there is limited information on the viruses infecting D. youngi. Hence, this study aimed to expand the knowledge about the viral diversity associated with D. youngi by sampling and pooling the lungs, liver, kidneys, heart, and intestines of all animals using high-throughput sequencing (HTS) on the Illumina MiSeq platform. A total of three complete and 10 nearly complete circular virus genomes were closely related to gemykrogvirus (Genomoviridae family), smacovirus (Smacoviridae family), and torque teno viruses (TTVs) (Anelloviridae family). In addition, three sequences of bat paramyxovirus were detected and found to be closely related to viruses reported in Pomona roundleaf bats and rodents. The present study provides a snapshot of the viral diversity associated with white-winged vampire bats and provides a baseline for comparison to viruses detected in future outbreaks

Serologic evidence of West Nile virus and Saint Louis encephalitis virus in horses from Southern Brazil

Flaviviruses as West Nile virus (WNV), Saint Louis encephalitis virus (SLEV), Ilhéus virus (ILHV), and Rocio virus (ROCV) are previously reported in different Brazilian regions, but studies in Southern Brazil are still scarce. To improve the information regarding flaviviruses in Southern Brazil, horse serum samples were analyzed using RT-qPCR and a commercial ELISA-Ab against WNV followed by PRNT75. All 1000 samples analyzed by real-time RT-PCR resulted negative. The 465 subsampled samples were analyzed by a commercial ELISA-Ab against WNV, and the 18.5% (86/465) positive samples were further analyzed by PRNT75. In the PRNT75, 13/86 and 2/86 horses were positive for SLEV and WNV, respectively. It was observed that 5.8% (13/226) of the farms presented at least one positive animal for SLEV in PRNT75, whereas 0.9% (2/226) for WNV. Apart from the lower seroprevalences identified when compared to data previously reported in other Brazilian regions, our results suggest that public health professionals must be aware of the presence of these potential zoonotic pathogens