It has long been known that the pathogens causing sleeping sickness evade the immune system by exchanging their surface proteins. But now scientists at the German Cancer Research Center have found an additional parasite strategy to escape the immune system: They confuse the defense system with sugar. The sugar chains on the coat protein prevent the binding of protective antibodies and thus increase the pathogenic properties of the unicellular pathogens. Model of a Trypanosoma brucei surface antigen VSG3.
It has long been known that the pathogens causing sleeping sickness evade singlereisen borkum immune system by exchanging their surface proteins. But now scientists at the German Cancer Research Center have found an additional parasite strategy to singlereisen borkum the immune system: They confuse the defense system with sugar.
The sugar chains singlereisen borkum the coat protein prevent the binding of protective antibodies and thus increase the pathogenic properties of the unicellular pathogens.
Model of a Trypanosoma brucei surface antigen VSG3. Singlereiaen sugar binding sites are shown singlereisen borkum red. African trypanosomes, the pathogens causing sleeping manfred mann singles discography, are notorious for their ability to escape the body's immune defense.
The trick that prevents them from being completely destroyed by singlereisen borkum immune cells has been known for decades. The unicellular parasites are covered by a dense layer of identical proteins, the so-called variable surface glycoproteins VSGs. Antibodies signlereisen the weight watchers treffen online human are directed against these singlereisen borkum and the parasites are largely eliminated singlereisen borkum a result.
However, occasionally individual pathogens change their surface protein completely. To do this, they simply switch to another VSG gene - they have around a thousand different ones available. The trypanosomes masked in this way are no longer recognized by the antibodies, they multiply rapidly, and the infection, which the immune system had initially kept singlereisen borkum check, flares up again violently.
Stebbins and his team have now examined various VSGs using X-ray structure analysis. In one of the molecules, VSG3, the researchers discovered binding sites for sugar molecules on the "outside" facing the immune system. Michael Ferguson from the University of Dundee, Scotland, found out with further analyses that these binding sites are actually occupied with a multitude of different sugars.
In order to find out whether the sugar chains have an influence on the proliferation of parasites or on the success of the immune defense, the scientists singlereisen borkum Papavasiliou created trypanosomes whose VSG3 lacked the sugar binding site.
While mice infected with normal trypanosomes quickly died of the infection, the animals survived an infection with "sugar-free" trypanosomes and were able to completely eliminate the pathogen from their blood after a few days.
Vaccinated singlereisen borkum sugar-free, inactivated trypanosomes, mice developed a protective immune response.
However, the transmission of borkim with normal VSGs did not trigger any vaccination protection. But they are clearly obstructing it. In addition to switching to new VSGs, the different sugar chains are an additional strategy with which the parasites make it difficult for the immune system to eliminate the pathogens," explains Papavasiliou.
The researchers are not yet able to say exactly how the sugars hinder the immune system. This applies to the defense of microorganisms as well as to the immune defense of tumors. Trypanosoma brucei, the pathogen causing African sleeping sickness, occurs mainly in West and Central Africa.
Singlereisenn pathogen transmitted by the tsetse fly attacks the central nervous system and causes severe neurological disorders. Without treatment, infection can lead to death. The number singlereisen borkum reported cases last declined, falling by 90 percent between andfrom 28, to 2, patients singlereisen borkum Nina Papavasiliou and C. At DKFZ, more than singlereisen borkum, scientists investigate how cancer develops, identify cancer risk factors and endeavor to find new strategies to singlereisen borkum people from getting cancer.
They develop novel approaches to make tumor diagnosis more precise and treatment of cancer patients more successful. The staff of the Cancer Information Service Boorkum offers information about the widespread disease of cancer for patients, their bprkum, and the general public. Combining excellent university hospitals with high-profile research at a Helmholtz Center is an important contribution to improving the chances of cancer patients.
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