Navigation Links
IRCM scientists find a novel research model for the study of auto-immune diseases
Date:7/3/2013

Montral, July 3, 2013 A team of researchers at the IRCM, led by Dr. Javier M. Di Noia in the Immunity and Viral Infections research division, discovered a novel research model for the study of auto-immune diseases. The Montral scientists are the first to find a way to separate two important mechanisms that improve the quality of antibodies. This study was featured in a recent issue of The Journal of Immunology.

Dr. Di Noia's team studies B cells, a group of white blood cells known as lymphocytes whose main function is to produce antibodies to fight against antigens. Antibodies are proteins used by the immune system to identify and neutralize foreign objects (antigens), such as bacteria and viruses, by precisely binding to them, thus making them an essential part of the immune system. Antibodies can come in different varieties (or classes), which perform different roles and adapt the immune response to eliminate each different toxin or pathogen they encounter. The body's great diversity of antibodies therefore allows the immune system to specifically neutralize an equally wide variety of antigens.

"Our project focused on two mechanisms that produce this wide variety of antibodies," says Dr. Di Noia, Director of the Mechanisms of Genetic Diversity research unit at the IRCM. "Because both processes are initiated by the same enzyme known as AID (activation-induced deaminase), it had previously been very difficult to study them separately. We were able to identify, for the first time, a mouse model in which the mechanisms could be analyzed independently during an acute immune response."

The two mechanisms in question are known as class switching and affinity maturation. Class switching is the process that allows a B cell to produce different classes of antibodies, so that a single antibody can be used by several different parts of the immune system. Affinity maturation, on the other hand, is the process by which B cells produce antibodies with increasingly stronger bonds to antigens during an immune response.

"Since eliminating AID would in turn completely eliminate affinity maturation and class switching, we focused on an enzyme called UNG, which is also involved in both processes," adds Astrid Zahn, research associate in Dr. Di Noia's laboratory and first author of the study. "When we analyzed mice lacking the UNG gene, we found that affinity maturation was normal but class switching was strongly reduced during acute immune responses, such as the response to immunization and against a viral infection."

"While over 100 AID-deficient patients have been identified, it is striking that only a handful of patients are known to be UNG-deficient," explains Dr. Zahn. "Our study, which shows that chronic antibody responses (those to environmental antigens) remain nearly normal without UNG, can explain why most UNG-deficient individuals are not detected among immunodeficient patients. Nevertheless, because we also found that acute antibody responses were significantly affected, we suspect that UNG-deficient people will, for example, respond very poorly to vaccination. In addition, as this work was conducted as part of a larger ongoing investigation of the complex relationship between AID and UNG, we believe that UNG might possibly act as a tumour-suppressor in B-cell lymphomas."

"Until now, it was difficult to study the relative importance of class switching and affinity maturation, and the impact of these two mechanisms on immune responses," concludes Dr. Di Noia. "Our study provides a novel model to study the contribution of these mechanisms in certain auto-immune diseases such as lupus and rheumatoid arthritis, or some infections like influenza."


'/>"/>

Contact: Julie Langelier
julie.langelier@ircm.qc.ca
514-987-5555
Institut de recherches cliniques de Montreal
Source:Eurekalert

Related medicine news :

1. Scientists solving the mystery of human consciousness
2. Scientists uncover multiple faces of deadly breast cancer
3. Scientists identify major source of cells defense against oxidative stress
4. Scientists tailor cell surface targeting system to hit organelle ZIP codes
5. Scientists rewrite rulebook on breast cancer in landmark global study
6. Warwick scientists uncover how checkpoint proteins bind chromosomes
7. NIH scientists link quickly spreading gene to Asian MRSA epidemic
8. Joslin scientists identify important mechanism that affects the aging process
9. Scripps Research scientists show how memory B cells stay in class to fight different infections
10. Scientists Map Melanomas Genome
11. A*STAR scientists discover switch to boost anti-viral response to fight infectious diseases
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/26/2017)... ... , ... “When the Stars Lead Home”: a poignant story of loss, determination, ... Weigel Douglas, an avid reader who lives in the Pacific Northwest with her husband, ... Hills Adventure Camp. She couldn’t be more grateful. , Twelve-year old Tizzy could not ...
(Date:5/26/2017)... ... May 26, 2017 , ... “Cactus Jack: Against All ... so many others. “Cactus Jack: Against All Odds” is the creation of published ... D. Hubbard is married to Jack Carlisle’s third child Jane. Walter. Walter and ...
(Date:5/24/2017)... York (PRWEB) , ... May 24, 2017 , ... Dr. ... vascular surgery in New York City. He is known for his distinguished expertise ... in vascular surgery, Dr. Benvenisty holds sub-specialty training in treating renovascular disease and ...
(Date:5/24/2017)... ... May 24, 2017 , ... Dr. Manju R. Kejriwal, a ... orthodontics, with or without a referral. Dr. Kejriwal understands the emotional and financial ... clear braces in Cincinnati, OH. Patients no longer need to feel the esthetic effects ...
(Date:5/24/2017)... , ... May 24, 2017 , ... ... completed Course II of the HP3 (High-Performance Periodontal Practice) continuing education (CE) series. ... the latest advancements in his field by attending numerous CE courses each year. ...
Breaking Medicine News(10 mins):
(Date:5/9/2017)... , May 9, 2017  Semler Scientific, Inc. ... technology solutions to improve the clinical effectiveness and ... for the first quarter ended March 31, 2017. ... enable our customers to identify when preventive care ... before events like heart attacks or strokes occur," ...
(Date:5/6/2017)... FALLS, N.Y. , May 5, 2017  Hill-Rom ... that will add approximately 100,000 square feet to its ... in September 2016 its commitment to bring more than ... , where Welch Allyn has maintained a significant ... will help accommodate these new positions, a large portion ...
(Date:5/4/2017)... 4, 2017  DarioHealth Corp. (NASDAQ: DRIO), a leading ... data solutions, today announced that it is teaming up ... Technologies Limited to lower diabetes healthcare costs in ... card, which is available throughout all provinces and territories ... be eligible for additional savings when shopping for Dario ...
Breaking Medicine Technology: