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
Improving memory with magnets
28.03.2017 | McGill University
Graphene-based neural probes probe brain activity in high resolution
28.03.2017 | Graphene Flagship
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Life Sciences
28.03.2017 | Information Technology
28.03.2017 | Physics and Astronomy