As people age, their immune systems weaken. Due to the shrinking of the thymus, where T cells normally mature and diversify, the population of these immune cells becomes smaller and cannot respond quickly to pathogens. But researchers at MIT and the Broad Institute have now found a way to reverse that decline by temporarily programming cells in the liver to improve T-cell function.
To create a “factory” for the T-cell-stimulating signals normally produced by the thymus, the researchers identified three key factors that normally promote the maturation of T cells and encoded them in mRNA sequences that could be delivered by lipid nanoparticles. When injected into the bloodstream, these particles accumulate in the liver and the mRNA is taken up by the organ’s chief cells, hepatocytes, which begin producing the protein encoded by the mRNA.
The aged mice that received the treatment showed much larger and more diverse T-cell populations in response to vaccination, and they also responded better to cancer immunotherapy treatments.
If this type of treatment is developed for human use, says Professor Feng Zhang, senior author of paper At work, “hopefully we can help people live free from disease for longer periods of their lives.”
