Many problems that arise before scientists have already been successfully solved by nature itself - you just need to feel free to learn from her creations. One of these teachers was the worst enemy of man - cancer cells. Scientists at the University of Pittsburgh (USA) have studied how cancer cells "hack" the immune system, and have applied this method to solve the fundamental problem of transplant rejection.
The natural barrier for cancer cells is the body's immune system, which acts in a very stereotyped manner - it seeks to destroy everything that it considers foreign, but does not touch the cells that it considers “its own”. When a tumor forms, cancer cells release the CCL22 protein, a marker that signals the immune T-leukocytes to mark these cells as "their own". After that, almost nothing prevents them from growing calmly and moving around the body.
When transplanting donor tissues and organs, the same problem arises - the immune system attacks foreign cells. Scientists decided to simply copy the method of cancerous tumors, adding synthetic capsules with CCL22 to the grafts. Much to their surprise, after the second series of injections, the immune system of the recipients began to completely ignore the transplanted tissue, which took root perfectly.
At the moment, the best result looks like this. Experienced rats were transplanted with tissues, organs and even whole paws, which function normally without signs of rejection for 200 days. This allows us to conclude that the effect is long-term, if not permanent. And it opens up tremendous opportunities in the field of transplantation, as well as cancer treatment - if we know the mechanism of hacking, then we can develop countermeasures against it.