Press Release
Athens, 5 November 2012

A common genetic polymorphism changes how the human immune system reacts to disease


Every day life experience tells us that not everyone’s body deals with disease the same way. Either it is for a viral infection or cancer, each person reacts differently and this is largely due to differences in how each individual’s immune system works. Scientists are now starting to find out that these different reactions are caused by the hereditary variability of the genes of our immune system. The immune system is a collection of specialized organs, cells and tissues in our body that are responsible for dealing with infections and diseases.

This knowledge is being expanded by researchers at the NCSR “Demokritos”. The research group is studying these genetic variations
trying to determine what exactly they do in order to help scientists develop new diagnostic protocols and effective treatments for human diseases. The research team, which among others includes the main researcher of the project, Dr. Irini Evnouchidou, and headed by Senior Researcher Dr. Efstratios Stratikos, discovered a possible mechanism by which one specific genetic variation in a recently discovered component of the immune system - a common “mutation” that one out of four people carry – makes some people more prone to some infections, including the Human Immunodeficiency Virus, the virus that is responsible for the development of AIDS.

This “mutation” is located in the gene of the enzyme ERAP2. ERAP2 along with his partner ERAP1, are enzymes whose job is to help the immune system figure out which cells are diseased. Imagine being in front of a fruit market stand, trying to select a ripe watermelon. You pick one but before you pay for it, the shop owner cuts a small piece in order to show to you that the fruit is nice and ripe. This is necessary because the watermelon has a thick skin and the customer cannot see its interior. In a similar fashion, the immune system needs to see a "piece" of the interior of the cell in order to understand whether it is diseased or not. ERAP2 plays the role of the knife and the sample that it cuts is called an antigenic peptide.

The NCSR Demokritos team discovered that a common
“mutation” in the gene of the enzyme ERAP2 changes the way it cuts the sample. As a result, the interior samples shown to the immune system (the antigenic peptides) can be slightly different resulting in either the efficient detection for some diseases or evasion from the immune system for others. These types of observations can explain why some people are resistant to being infected by HIV, regardless of repeated exposed to it. Moreover, this particular finding opens new avenues for better individualized medicine and defines a new pharmaceutical target for the development of therapeutic immunotherapy.

Applying the knowledge of this discovery to the study of many different diseases, scientists can draw a map that will show how
genetic variations in ERAP1 and ERAP2 enzymes can influence our resistance to a range of life-threatening diseases.

The findings of NCSR “Demokritos” researchers, along with collaborators from University of Athens, the research center Alexander Fleming and the University of Michigan were published in September 2012 in the Journal of Immunology as a featured article and were recommended by the Faculty of 1000 review board.

The scientists that participated in this collaborative research project are: Efstratios Stratikos, Irini Evnouchidou, James Birtley, Efthalia Zervoudi, Irene Mavridis, Emmanuel Saridakis, Petros Giastas and Athanasios Papakyriakou from the NCSR “Demokritos”, George Panayotou and Martina Samiotaki from the BSRC “Alexander Fleming”, Olivia Petrakis and Dimitris Georgiadis from the University of Athens as well as Sergey Seregin and Andrea Amalfitano from the Michigan State University.

Relative links: 

Website of the Protein Chemistry Laboratory of the NCSR “Demokritos”:

Website of the Laboratory of Structural & Supramolecular Chemistry of the NCSR “Demokritos”:


Dr. Irini Evnouchidou, main researcher of the project and postgraduate scholar at the Protein Chemistry Laboratory of the NCSR “Demokritos during the run of the project. Dr. Evnouchidou is currently a researcher at the INSERM in Paris
Dr. James Birtley, postdoctoral researcher at the Laboratory of Structural & Supramolecular Chemistry of the NCSR “Demokritos” during the run of the project. Dr. Birtley is currently a researcher at the University of Massachusetts Medical School

For the N.C.S.R. "Demokritos"

The National Center for Scientific Research (NCSR) "Demokritos" is the largest multidisciplinary research center in the country with substantial scientific research, technological and educational activities in the areas of: Health, Biology and Biotechnology, New Materials Micro & Nanotechnology, Environment - Energy and Sustainable Development, Information Technology & Telecommunications, Nuclear Physics & Elementary Particle Physics, Nuclear Technology & Radiation Protection, Cultural Heritage.


For more information please contact:

N.C.S.R. "Demokritos"
Public Relations & Press Office
Τel. +30-210-650-3002, 3040
Fax: 210-650-3260