Epstein-Barr virus (EBV) prevents infected cells from being attacked by the immune system. The virus drives production of small molecules, so-called microRNAs, that suppress alarm signals sent out by the infected cell. Scientists at Helmholtz Zentrum München have elucidated this previously unknown mechanism.
The EBV virus, first described by the English virologists Michael Epstein and Yvonne M. Barr, is found in the majority of the world’s population, but is usually held in check by the immune system. Nevertheless, the body is unable to eliminate this pathogen completely.
The team of scientists led by Prof. Wolfgang Hammerschmidt, head of the Research Unit Gene Vectors at Helmholtz Zentrum München and a member of the German Center for Infection Research (DZIF), is striving to find out the reasons behind this.
Hide-and-seek: EBV makes itself invisible
“Our new studies show that by means of microRNAs, the virus prevents the infected cell from alerting the immune system,” said Hammerschmidt, summarizing the findings. EBV usually hides in B cells, a class of white blood cells. If they are infected by EBV, the virus induces the cells to proliferate and thus to expand the reservoir of viruses. The B cells usually respond with an alarm signal to the immune system: They present molecules of the virus on their surface and secrete inflammatory cytokines to attract immune cells.
“It's just this alarm signal that's suppressed by microRNAs made by the virus,” said Manuel Albanese, a scientist in the Research Unit Gene Vectors. His colleague Takanobu Tagawa added: “The microRNAs block production of the proteins that would ring this alarm.” The two doctoral students share the lead authorship of the two publications in the Proceedings of the National Academy of Sciences and in the Journal of Experimental Medicine.*
New approach may be promising for cancer therapy
Since the EBV virus drives division of B cells and thereby causes particular forms of cancer, the researchers are considering how to apply these findings to cancer therapy. “The mechanism we discovered renders killer T cells and helper T cells inactive, even when they directly face the infected cell,” said study leader Hammerschmidt.** “If it were possible to disrupt this blockade, this could be an interesting approach to treat cancer: the immune system could then better fight tumors that are triggered by EBV.“ For other diseases, clinical studies on active substances that shut off specific microRNAs have already started, the authors say.
* microRNAs (miRNAs) are noncoding RNAs that play an important role in gene regulation and especially in the silencing of genes. Generally, they have a size of 21 to 23 nucleotides and are very short – hence the name.
** Killer T cells (also known as CD8 T cells) can destroy the infected cells, thus preventing the virus from multiplying. Helper T cells (also called CD4 T-cells) support them and also ensure the production of antibodies against the virus.
About a year ago, scientists of the Gene Vectors Research Unit at Helmholtz Zentrum München discovered another mechanism the EBV virus uses to hide in human cells. Here the LMP2A protein plays a crucial role: http://www.helmholtz-muenchen.de/en/press-media/press-releases/2015/press-releas...
Tagawa, T. & Albanese, M. et al. (2016): Epstein-Barr Viral miRNAs Inhibit Antiviral CD4+ T Cell Responses Targeting IL-12 and Peptide Processing. Journal of Experimental Medicine, doi: 10.1084/jem.20160248
Albanese, M. & Tagawa, T. et al. (2016): Epstein-Barr virus miRNAs inhibit immune surveillance by virus-specific CD8+ T cells. Proceedings of the National Academy of Sciences (PNAS), doi: 10.1073/pnas.1605884113
The Helmholtz Zentrum München, the German Research Center for Environmental Health, pursues the goal of developing personalized medical approaches for the prevention and therapy of major common diseases such as diabetes and lung diseases. To achieve this, it investigates the interaction of genetics, environmental factors and lifestyle. The Helmholtz Zentrum München is headquartered in Neuherberg in the north of Munich and has about 2,300 staff members. It is a member of the Helmholtz Association, a community of 18 scientific-technical and medical-biological research centers with a total of about 37,000 staff members. http://www.helmholtz-muenchen.de/en
The Research Unit Gene Vectors studies EBV's molecular functions to understand how the virus contributes to different types of disease. The scientists analyse the immune system of virus carriers to find out how EBV and other herpes viruses are kept in check, and why immune control has failed in patients with disease. They also investigate the origins of cancers of the immune system - lymphoma and leukaemia. Their ultimate goal is to develop new drugs, vaccines and cell-based therapies in order to efficiently treat or – preferentially – prevent infectious diseases and cancer. http://www.helmholtz-muenchen.de/en/agv
At the German Center for Infection Research (DZIF), over 500 scientists from 35 institutions nationwide jointly develop new approaches for the prevention, diagnosis and treatment of infectious diseases. Their aim is to translate research results into clinical practice rapidly and effectively. With this, the DZIF paves the way for developing new vaccines, diagnostics and drugs in the fight against infections. http://www.dzif.de.
Contact for the media:
Department of Communication, Helmholtz Zentrum München - German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg - Tel. +49 89 3187 2238 - Fax: +49 89 3187 3324 - E-mail: firstname.lastname@example.org
Scientific Contact at Helmholtz Zentrum München:
Prof. Dr. Wolfgang Hammerschmidt, Helmholtz Zentrum München - German Research Center for Environmental Health, Research Unit Gene Vectors, Marchioninistraße 25, 81377 München - Tel. +49 89 3187 1506, E-mail: email@example.com
Sonja Opitz | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Unique genome architectures after fertilisation in single-cell embryos
30.03.2017 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
Transport of molecular motors into cilia
28.03.2017 | Aarhus University
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
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering