The ability of a human body to resist pathogenic factors is under control of immune cells, the most important of which are lymphocytes. The first subtype called effector lymphocytes, contacts with viruses and bacteria or cells affected by them and kill the patogenes.
After the pathogens are destroyed, such lymphocytes should die as well, otherwise they may turn into autoimmune cells causing autoimmune diseases and allergies by attacking other normal cells of the same body. Another subtype, regulatory T-cells, prevents the development of such aggressive autoimmune cells.
Scientists are aware that regulatory T-cells are able to suppress effector lymphocytes upon direct contact by activating special receptors on their membranes. Regulatory T-cells contact with the surface of the target cell and activate self-destruction processes.
"The mechanisms of autoimmunity suppression by regulatory T-cells are widely studied. However, it is not always obvious how they manage to react over distance. In our work we've described a completely new distant (contact independent) mechanism based on "accelerated ageing" of effector lymphocytes," says Dmitry Zhdanov, assistant professor of the department biochemistry named after Academician T.T. Berezov at RUDN Institute of Medicine.
Each cell in our body has a limited number of divisions. The regulatory mechanism for this limitation is quite simple and determined by nature itself. Upon each new division the end regions of chromosomes called telomeres are reduced. After a certain number of divisions, the telomeres become critically short and the cells become aged (they are still alive but unable to divide).
Afterwards these cells die. Unlike the majority of other cells, immune cells have the enzyme called telomerase that synthesized telomeres. This allows lymphocytes to have more division instances and quickly reproduce when a body is hit by an infection.
RUDN biochemists co-cultivated effector autoimmune lymphocytes and regulatory T-cells separated with a special membrane in one culture flask for a long time. The cells were unable to contact directly, but could distantly exchange soluble substances.
It turned out that regulatory T-cells were able to inhibit the activity of telomerase in effector lymphocytes. Long-term cultivation of autoimmune lymphocytes with inactive telomerase caused their telomere loss and cell death. The effect was observed not only in the artificial conditions of cell co-cultivation, but also in living mice.
"Based on the obtained results we've discribed a new, previously unknown mechanism of autoimmunity regulation based on physiological ageing of immune cells and the activation of their self-destruction processes. Obviously, this process is a fundamental one to support cell functions and determine the fate of the cells. The understanding of this mechanism may be useful for the development of treatments for autoimmune diseases and prevention of implant rejection," concludes Dmitry Zhdanov.
Valeriya V. Antonova | EurekAlert!
Russian scientists show changes in the erythrocyte nanostructure under stress
22.02.2019 | Lobachevsky University
How the intestinal fungus Candida albicans shapes our immune system
22.02.2019 | Exzellenzcluster Präzisionsmedizin für chronische Entzündungserkrankungen
An international research team including astronomers from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has combined radio telescopes from five continents to prove the existence of a narrow stream of material, a so-called jet, emerging from the only gravitational wave event involving two neutron stars observed so far. With its high sensitivity and excellent performance, the 100-m radio telescope in Effelsberg played an important role in the observations.
In August 2017, two neutron stars were observed colliding, producing gravitational waves that were detected by the American LIGO and European Virgo detectors....
Up to now, OLEDs have been used exclusively as a novel lighting technology for use in luminaires and lamps. However, flexible organic technology can offer much more: as an active lighting surface, it can be combined with a wide variety of materials, not just to modify but to revolutionize the functionality and design of countless existing products. To exemplify this, the Fraunhofer FEP together with the company EMDE development of light GmbH will be presenting hybrid flexible OLEDs integrated into textile designs within the EU-funded project PI-SCALE for the first time at LOPEC (March 19-21, 2019 in Munich, Germany) as examples of some of the many possible applications.
The Fraunhofer FEP, a provider of research and development services in the field of organic electronics, has long been involved in the development of...
For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.
The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...
Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens
Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...
Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light
When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...
11.02.2019 | Event News
30.01.2019 | Event News
16.01.2019 | Event News
22.02.2019 | Physics and Astronomy
22.02.2019 | Materials Sciences
22.02.2019 | Life Sciences