Based on research from scientists, studies have shown that rats accept transplanted limbs through a trick that nobody ever thought about. In this article, you will learn how cancer cells have effectively changed a rat’s defenses to ignore foreign tissue.

How it is Done

When rats are injected with engineered microparticles into the transplanted tissue, the microparticles deliver a signaling protein known as CCL22 that’s covered from cancer cells. These cells (regulatory T cells) attract specialized immune cells and mark the rat’s new tissue as “self”. Therefore, it protects the tissue from an attack of immune defenses that would normally attack foreign material.

Most rats that were treated with microparticles maintained healthy limbs. Rats that were not lucky didn’t get the treatment and rejected the transplant. Regulatory T cells, which act to suppress immune responses and prevent them from attacking a host’s own issue, moved to the site of the transplant where there was a decrease of inflammation.

How Did This Come About?

Research for the study on rats began in March. Infused with engineered microparticles tolerated hind limb transplantation from another rat. Afterward, for more than 200 days, even in the absence of drugs that suppress immune responses, researchers carried more experiments from the rats to see what else they could find.

The practice was inspired by Steven Little, a chemical engineer at the University of Pittsburg who explained: “I wonder if we were able to synthetically mimic [what cancer cells do], could we trick the body into accepting a transplant?” 

What Does This Mean for the Future?

The study deemed that the rats are able to keep their new limbs, but now pigs are going to be tested for research, in order to determine the best microparticle doses.