Immune effects of tire-derived nanoplastics in human lymphoid tissue: an ex vivo study

Abstract (Swedish)

Plastic pollution in the natural environment is a growing concern, and due to its limited biodegradability, it continues to accumulate. Over time, plastics naturally break down into micro- and nanoplastics, which can be inhaled and ingested by humans. A significant share of these particles is a result of tire abrasion. These particles have been found in several human tissues, but knowledge of their effects on human immune cells remains limited. The palatine tonsils are located at the interface between the respiratory and gastrointestinal tracts and serve as a good model for human exposure to these nanoplastics.

This study employs an ex vivo model to stimulate 300 μm precision-cut tonsil slices with tire-derived nanoplastics, aiming to evaluate their effects on T cells and dendritic cells. The slices are cultured for 72 hours, after which activation and phenotypic markers are analyzed via flow cytometry.

The results indicated that nanoplastics do not appear to alter T cell population frequencies. Nonetheless, there are signs that nanoplastics may enhance cell activation and promote a shift in T cell subtypes toward a lymphoid-homing phenotype. Because the dendritic cell count was very low, it was challenging to draw definitive conclusions about the treatment's impact on these cells, and additional donors would be necessary to obtain more reliable results.

A key challenge with the model was that the positive and negative controls exhibited similar activation levels, which would need to be addressed to achieve more reliable results where the treatment effects are more distinct.

Popular Abstract

For the past couple of decades, the presence of plastics in our everyday lives has increased. Our clothes are made of it, our food is packaged in it, and the air we breathe is full of it. But how do they affect our immune system?

Plastic pollution is a growing concern, and plastic continues to accumulate in the natural environment. Plastic is not naturally degradable; instead, it continues to break down into smaller particles without disappearing. When these particles are smaller than 1 μm (about 100 times thinner than a strand of hair), they are called nanoplastics. Currently, there is limited knowledge of how these tiny particles affect human health. To gain a greater understanding of this, this study investigated whether they could alter the behavior of human immune cells.

To study this, human tonsils were used. Since tonsils are located in the back of the throat, they are exposed to both inhaled and ingested particles, making them a good organ to study how environmental particles such as nanoplastics affect immune cells. After surgical removal, human tonsils were cut with a machine using a razor blade, producing very thin slices. These slices were exposed to tire-derived nanoplastics. Tire-derived nanoplastics are normally present in the air we breathe and are released from tires when driving. The slices were then analyzed using a method called flow cytometry. Flow cytometry works by utilizing different kinds of antibodies, where each kind has a specific color. An antibody is a type of protein that can only bind one specific kind of molecule. The antibody is like a key that only fits one lock, or in this case, one molecule. When analyzing immune cells using flow cytometry, you can then tell which kinds of antibodies have bound to a cell based on the colors the cell displays. Since each type of antibody can only bind a certain kind of molecule, the colors show which molecules are present on the cell and how much of each molecule is present. Knowing this tells a story about what kind of cell it is and whether it has been activated, meaning it is ready to fight off invaders.

T cells are a type of immune cell that both activate other immune cells and kill infected cells. The results showed that in one type of T cells, a molecule called CCR7 increased. This molecule is linked to how T cells move in the body and suggests that the T cells that were exposed to tire-derived nanoplastics were more likely to move towards immune tissues such as the tonsils. Two molecules associated with T cell activation were also investigated but no increase in these molecules after exposure to tire-derived nanoplastics was observed.

Another important type of immune cell is the dendritic cell. Dendritic cells help the immune system recognize potential threats. They take up foreign material and show pieces of it to T cells, which helps the T cells to initiate an immune response. When investigating the effect of tire-derived nanoplastics on dendritic cells, two molecules that usually increase when the dendritic cells encounter foreign material were investigated. The results did not show an increase in these molecules for the cells that were exposed to tire-derived nanoplastics.

• author: Kvist, Hugo
• supervisor: Christina Sakellariou; Johanna Karlsson; Ghjuvan Micaelu Grimaud
• organization: Department of Immunotechnology
• course: KIMM05 20261
• year: 2026
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences; Technology and Engineering
• keywords: Immunotechnology, Nanoplastics, PCTS, Ex vivo model
• language: English
• id: 9248771
• date added to LUP: 2026-08-21 10:39:24
• date last changed: 2026-08-21 10:39:24