Redesigning the Immune Cells
Waiting lists are long and finding a suitable donor is a game of probabilities, but organ transplants are life-saving procedures that take place for tens of thousands of people every year.
Of the thousands that receive a transplant however, the largest obstacles to overcome for many of them is organ rejection, where the body’s immune system treats the organ as an invader and destroys it. Scientists in Augusta, Georgia may have discovered a way to combat this final hurdle to successful organ transplant and the possible applications are far-reaching.
The body’s automatic immune response is to attack and destroy a transplanted organ because it is foreign tissue, just like viruses, bacteria and cancer cells are foreign and need to be destroyed. This process of attacking the organ is called immunologic rejection.
Anti-rejection drugs are employed to stop the immune system from working effectively and attacking the organ, but this leaves patients open to severe risk of infection and requires lifelong drug-dependency.
Scientists at the Medical College of Georgia, Augusta have come up with a novel approach to dealing with organ rejection, one that doesn’t require complex drug regimes or decimation of the immune system.
Dr. Anatolij Horuzsko, reproductive immunologist at the MCG Centre for Molecular Chaperone/Radiobiology and Cancer Virology, has unveiled “designer” immune cells to help patients manage their new organ.
These designer cells are degradable microparticles that deliver a large dose of a natural immuno-suppresor called HLA-G (human leukocyte antigen G) to dendritic cells in the body, cells that dictate what the immune system should attack. The dendrites are stopped from giving orders to attack the foreign tissue of the organ and it’s allowed to function as normal.
Microparticle therapy, already successful in skin grafts on mice, would be required for a period of weeks after which time dendritic cells would learn to automatically ignore the organ tissue.
“It’s like a calming effect and once tolerance is established, we don’t need it any more” Dr. Horuzsko says.
In straight comparison with natural HLA-G suppressant behaviour,
HLA-G microparticles have dendritic markers, making them faster and more efficient at sending signals. Without markers, they lack direction and so would be devoured by macrophages – the body’s garbage eaters.
Along with removing the need for immuno-suppressant drugs and their associated health risks, microparticles have the potential to do more than protect donor organs.
Diseases in the body such as arthritis and multiple sclerosis work by misdirection of the immune system to destroy healthy tissue, again microparticles such as these could be useful in sending messages to prevent an attack and in the case of tumours, where the immune system is working overtime, the microparticles could be used in opposition and HLA-G could be blocked completely.
If further research is successful, it may be just 5 or 6 years before designer immune cells are making their way through the systems of thousands of people all over the world – saving their lives by saving the organs they may have waited months or years to obtain.
