Epstein barr virus in dogs

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.

They found no evidence of the same DNA in the healthy dogs. 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.

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. Materials provided by University of Pennsylvania. Note: Content may be edited for style and length. Science News. Their work was published online March 8 in the journal Virology.

Story Source: Materials provided by University of Pennsylvania. Evidence of an oncogenic gammaherpesvirus in domestic dogs. Virology , ; DOI: About one third of infected teenagers and young adults nevertheless develop infectious mononucleosis, also known as glandular fever or kissing disease, which usually wears off after a few weeks. In rare cases, however, the virus causes cancer, particularly lymphomas and cancers of the stomach and of the nasopharynx.

Scientists have been trying for a long time to elucidate how the viruses reprogram cells into becoming cancer cells. In their present publication, Delecluse, in collaboration with Ingrid Hoffmann, also from the DKFZ, and their respective groups present a new and surprising explanation for this phenomenon.

The scientists have shown for the first time that a protein component of the virus itself promotes the development of cancer. When a dividing cell comes in contact with Epstein-Barr viruses, a viral protein present in the infectious particle called BNRF1 frequently leads to the formation of an excessive number of spindle poles centrosomes.

As a result, the chromosomes are no longer divided equally and accurately between the two daughter cells -- a known and acknowledged cancer risk factor. By contrast, Epstein-Barr viruses that had been made deficient of BNRF1 did not interfere with chromosome distribution to the daughter cells. EBV, a member of the herpes virus family, infects B cells of the immune system.

The viruses normally remain silent in a few infected cells, but occasionally they reactivate to produce viral offspring that infects nearby cells. As a consequence, these cells come in close contact with the harmful viral protein BNRF1, thus having a greater risk of transforming into cancer cells.

Usually, the genetic material of the viruses needs to be permanently present in the infected cell, thus causing the activation of one or several viral genes that cause cancer development.

However, these gene products are not present in the infectious particle itself. 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.

They found no evidence of the same DNA in the healthy dogs. 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.

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. 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.

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