Home  >  News
you can get e-magazine links on WhatsApp.Click here
Pioma_Lactic
Research + Font Resize -

Research breakthrough selectively represses the immune system

Bethesda, Maryland
Wednesday, November 21, 2012, 14:00 Hrs  [IST]

The National Institutes of Health (NIH) researchers have developed innovative technology to selectively inhibit the part of the immune system responsible for attacking myelin-the insulating material that encases nerve fibres and facilitates electrical communication between brain cells. The research was supported by NIH’s National Institute of Neurological Disorders and Stroke (NS026543), the Myelin Repair Foundation, and the Juvenile Diabetes Research Foundation (17-2011-343).

Autoimmune disorders occur when T-cells-a type of white blood cell within the immune system-mistake the body’s own tissues for a foreign substance and attack them. Current treatment for autoimmune disorders involves the use of immunosuppressant drugs which tamp down the overall activity of the immune system. However, these medications leave patients susceptible to infections and increase their risk of cancer as the immune system’s normal ability to identify and destroy aberrant cells within the body is compromised.

Supported by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) at NIH, Drs Stephen Miller and Lonnie Shea at Northwestern University, Evanston, teamed up with researchers at the University of Sydney, and the Myelin Repair Foundation in Saratoga, California to come up with a novel way of repressing only the part of the immune system that causes autoimmune disorders while leaving the rest of the system intact.

The new research takes advantage of a natural safeguard employed by the body to prevent autoreactive T-cells-which recognise and have the potential to attack the body’s healthy tissues-from becoming active.

“We’re trying to do something that interfaces with the natural processes in the body,” said Shea. “The body has natural mechanisms for shutting down an immune response that is inappropriate, and we’re really just looking to tap into that.”

One of these natural mechanisms involves the ongoing clearance of apoptotic, or dying, cells from the body. When a cell dies, it releases chemicals that attract specific cells of the immune system called macrophages. These macrophages gobble up the dying cell and deliver it to the spleen where it presents self-antigens-tiny portions of proteins from the dying cell-to a pool of T-cells. In order to prevent auto-reactive T-cells from being activated, macrophages initiate the repression of any T-cells capable of binding to the self-antigens.

Dr Miller was the first to demonstrate that by coupling a specific self-antigen such as myelin to apoptotic cells, one could tap into this natural mechanism to suppress T-cells that would normally attack the myelin. The lab spent decades demonstrating that they could generate antigen-specific immune suppression in various animal models of autoimmune diseases. Recently, they initiated a preliminary clinical trial with collaborators in Germany to test the safety of injecting the antigen-bound apoptotic cells into patients with MS. While the trial successfully demonstrated that the injections were safe, it also highlighted a key problem with using cells as a vehicle for antigen delivery.

"Cellular therapy is extremely expensive as it needs to be carried out in a large medical centre that has the capability to isolate patient’s white blood cells under sterile conditions and to re-infuse those antigen-coupled cells back into the patients," said Miller. "It’s a costly, difficult, and time-consuming procedure."

Thus began a collaboration with Dr Shea, a bioengineer at Northwestern University, to discuss the possibility of developing a surrogate for the apoptotic cells. After trying out various formulations, his lab successfully linked the desired antigens to microscopic, biodegradable particles which they predicted would be taken up by circulating macrophages similar to apoptotic cells.

Much to their amazement, when tested by the Miller lab, the antigen-bound particles were just as good, if not better, at inducing T-cell tolerance in animal models of autoimmune disorders.

Using their myelin-bound particles, the researchers were able to both prevent the initiation of MS in their mouse model as well as inhibit its progression when injected immediately following the first sign of clinical symptoms.

The research team is now hoping to begin phase I clinical trials using this new technology. The material that makes up the particles has already been approved by the US Food and Drug Administration (FDA) and is currently used in resorbable sutures as well as in clinical trials to deliver anti-cancer agents. Miller believes that the proven safety record of these particles along with their ability to be easily produced using good manufacturing practices will make it easier to translate their discovery into clinical use.

"I think we’ve come up with a very potent way to induce tolerance that can be easily translated into clinical practice. We’re doing everything we can now to take this forward," said Miller.

In addition to its potential use for the treatment of MS, the researchers have shown in the lab that their therapy can induce tolerance for other autoimmune diseases such as type I diabetes and specific food allergies. They also speculate that transplant patients could benefit from the treatment which has the potential to retract the body’s natural immune response against a transplanted organ. Dr Christine Kelley, NIBIB director of the Division of Science and Technology, points to the unique collaboration between scientists and engineers that made this advance a reality.

"This discovery is testimony to the importance of multidisciplinary research efforts in healthcare," said Kelley. "The combined expertise of these immunology and bioengineering researchers has resulted in a valuable new perspective on treating autoimmune disorders."

NIBIB’s mission is to support multidisciplinary research and research training at the crossroads of engineering and the biological and physical sciences. NIBIB supports emerging technology research and development within its internal laboratories and through grants, collaborations, and training.

NINDS is the nation’s leading funder of research on the brain and nervous system. The NINDS mission is to reduce the burden of neurological disease – a burden borne by every age group, by every segment of society, by people all over the world.

NIH, the nation's medical research agency, and is a component of the US Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases.




















 

*POST YOUR COMMENT
Comments
* Name :     
* Email :    
  Website :  
   
     
 
 
 
Copyright © 2016 Saffron Media Pvt. Ltd |