Now a team of researchers from the University of Pennsylvania School of Veterinary Medicine and Penn's Perelman School of Medicine has the first evidence that an Epstein Barr-like virus can infect and may also be responsible for causing lymphomas in man's best friend.
The findings suggest that domestic dogs possess a similar biology to humans with respect to EBV infection. That could allow scientists to study dogs to help uncover the mechanisms by which EBV leads to cancer in certain people.
"There are no large-animal spontaneous models of EBV infection and virus-associated disease, and most studies investigating viral disease are performed in non-human primates, which are very expensive," said Nicola Mason, senior author of the study and an assistant professor of medicine and pathobiology at Penn Vet. "Discovering that dogs can get infected with this virus like people do may provide us with a long-sought-after model for EBV-associated disease."
Mason's team at Penn Vet included Shih-Hung Huang, Philip Kozak, Jessica Kim, George Habineza-Ndikuyeze, Charles Meade, Anita Gaurnier-Hausser and Reema Patel. The team worked closely with Erle Robertson, professor of microbiology at the Perelman School of Medicine.
Their work was published online March 8 in the journal Virology.
In humans, the Epstein Barr virus infects B cells. After an acute phase of infection, of which many people are not even aware, the virus goes into a latent phase. Most people show no symptoms during this phase, but, in some, EBV promotes unnatural growth of B cells, which contributes to the development of lymphoma.
Meanwhile, dogs develop lymphomas that share some characteristics with the human equivalents. These conditions are relatively common in certain breeds. In golden retrievers, for instance, one out of every eight dogs develops lymphoma.
Yet, "the paradigm up until now was that EBV only infects humans," Mason said. "It is an extremely successful virus, and most people are infected. Since humans and domestic dogs have cohabited for around 15,000 years, we hypothesized that the virus may have adapted to another host. "
To search for evidence of infection, Mason and colleagues obtained samples of blood from client-owned dogs of various breeds brought to Penn Vet for care. In 48 dogs with lymphoma and 41 without the disease, the researchers first looked to see if the pets had antibodies against proteins specific to the EBV capsid, the protein shell of the virus. The test is nearly identical to one that physicians use to detect exposure to EBV in humans.
The researchers observed that eight of the dogs with lymphoma and three of those without it had high levels of antibodies against EBV proteins, indicating that a portion of the dogs had been exposed to a virus very similar to EBV.
While the presence of antibodies confirms that a dog has been exposed to a virus, the team wanted to know whether the virus had a direct association with the tumors in dogs with lymphoma. Finding viral elements, including DNA, within lymphomas in humans is an indication that the tumor is associated with the virus, therefore Penn researchers looked to see if they could find virus in the dog tumors.
Using the polymerase chain reaction, which amplifies specific DNA sequences, the researchers analyzed lymph nodes of dogs with and without B cell lymphoma. In two dogs with lymphoma, they were able to identify a portion of DNA very similar to a sequence in EBV. They found no evidence of the same DNA in the healthy dogs.
They repeated similar tests with other stretches of EBV DNA, finding evidence of EBV-like DNA in the cancer cells of three of nine dogs with lymphoma. They also identified a virus-associated protein in the malignant lymph nodes of two of nine dogs with lymphoma.
Finally, examining cancerous B cells under an electron microscope revealed what appeared to be viral particles, similar to what what has been seen in the tumor cells of humans with EBV-linked lymphomas.
Taken together, the researchers' discoveries indicate that some dogs are naturally infected with a virus similar or identical to EBV and that, as in humans, the virus appears linked in certain cases with canine lymphomas.
That such a large percentage of humans are exposed to EBV and yet only a small fraction develop cancers indicates that there may be a genetic component to EBV-associated cancer susceptibility.
"With additional studies within certain breeds of dog," Mason said, "we hope to provide insights into genetic factors that may predispose to virus associated lymphoma. Furthermore, this spontaneous dog model may help us evaluate new treatments for EBV-related lymphomas or investigate strategies to prevent those cancers from developing in the first place."
The study was supported by the University of Pennsylvania's Veterinary Center for Infectious Disease, the Abramson Family Cancer Research Institute at the University of Pennsylvania and the National Cancer Institute.
Katherine Unger Baillie | EurekAlert!
Further reports about: > B cells > Burkitt's lymphomas > DNA > DNA sequence > EBV > EBV proteins > EBV-associated disease > Epstein Barr-like virus > Medicine > Veterinary Public Health > development of lymphoma > domestic dogs > kissing disease > lymph node > lymphoma > mononucleosis > non-Hodgkin's
One gene closer to regenerative therapy for muscular disorders
01.06.2017 | Cincinnati Children's Hospital Medical Center
The gut microbiota plays a key role in treatment with classic diabetes medication
01.06.2017 | University of Gothenburg
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology