A virus invades the body and the immune system begins to work: Antibodies develop that fight the infection. At the same time, an immune memory builds up so that antibodies can be quickly made available in the event of a new infection. Surprisingly, antibodies can also form against polyethylene glycol (PEG), a molecule with a fairly simple structure.

In addition to cosmetic products - from creams, perfumes and lotions to lipstick - polyethylene glycol is also used in medicine. Here, it serves as a kind of camouflage coat against the body’s own immune system, thus increasing the circulation time of an active ingredient in the blood.

“For us, PEG is interesting for coating nano-sized drug carriers with it,” says Svenja Morsbach, group leader in Katharina Landfester’s department at the MPI for Polymer Research. In this way, the researchers achieve a longer circulation time for the drug capsules, which are only nanometers in size and could be an important component in novel cancer therapies in the future, for example.

In their studies, the team led by Morsbach and Landfester examined more than 500 blood samples from patients taken in 2019. “The antibodies formed against PEG attach themselves to the coated nanocarriers, thus counteracting the effect that is actually desired: the nanocarrier becomes visible to the immune system and is removed before it can exert its effect,” explains Katharina Landfester, director of the department.

Very interesting! I wonder what they will replace PEG with.