Investigation of per- and polyfluoroalkyl substances (PFAS) toxicity using a human dendritic cell model

Abstract

Per- and polyfluoroalkyl substances (PFAS) are persistent synthetic chemicals widely used in consumer and industrial products. Increasing evidence of their adverse health effects has intensified the need to understand their impact on human immune function. This study assessed PFAS toxicity using a human dendritic cell model by focusing on gene expression and surface marker modulation, as well as alternative culture media.
SenzaCell™ cells were exposed to 11 substances, including PFAS and controls, and analyzed using next-generation sequencing (NGS) to support future biomarker discovery. Further, cytotoxicity and CD86 activation marker expression were evaluated.
No PFAS showed outright cytotoxicity at the tested concentrations, however, perfluorooctane sulphonate (PFOS) decreased CD86 expression at 100 ppm, and both PFOS and hexafluoropropylene oxide dimer acid, significantly reduced relative cell viability to around 95 %. Two-step exposures with PFAS followed by either p-phenylenediamine (PPD), a known sensitizer, or lipopolysaccharide (LPS), a bacterial endotoxin, were performed to evaluate the PFAS ability to modulate immune activation. CD80 and CD86 expression were measured and the results showed that PFOS consistently downregulated CD86 expression. However, the results do not exclude the possibility that other PFAS may exert immunomodulatory effects through different mechanisms.
Additionally, alternative culture media were evaluated to replace fetal bovine serum (FBS) and support extracellular vesicle (EV) research. Media supplemented with EV-depleted FBS supported cell growth and yielded a similar immune phenotype, facilitating future PFAS–EV interaction studies. In contrast, a chemically defined, animal-free media did not support SenzaCell™ viability, indicating further development is required for animal-free culture alternatives.

Popular Abstract

Tracking the toxic trail of PFAS: Cellular clues to the risks of “Forever Chemicals”
Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals found in everything from non-stick cookware to firefighting foam. As these chemicals do not break down easily, PFAS accumulates in the environment and the human body. Even though their widespread presence is well documented, there is still much we don't understand about their impact on human health, especially on the immune system.
Immune cells are a crucial component of the body’s defense system. They continuously monitor the presence of harmful substances and when necessary, initiate specific responses to eliminate invading organisms. A remarkable feature of certain immune cells is their ability to 'remember' past threats, enabling a faster and more effective response to re-exposure. A clever invention to exploit this ability is the use of vaccines. Exposing the body to a small harmless amount of the potentially harmful organism, allowing the immune system to build a memory and prepare for future infections. However, PFAS have been shown to impair proper immune cell function, and the effect of vaccines, not to mention the several diseases such as cancer linked to PFAS exposure.
This study aimed to deepen our understanding of identifiable changes in immune cells that may indicate or predict PFAS toxicity. The study found that perfluorooctane sulphonate (PFOS) and Hexafluoropropylene oxide dimer acid (HFPO-DA), somewhat reduced the cell populations, however, no PFAS had direct toxic effects. Additionally, it was found that PFOS was the substance which showed the most prominent signs of affecting immune cells as it reduced the cellular marker cluster of differentiation 86 (CD86), which is an important tool for immune cells to activate other parts of the immune response. PFOS also showed indications of affecting other immune markers, CD80 and CD14, but no significant results could be drawn regarding these markers. To enable definitive conclusions and ultimately develop a predictive tool for PFAS toxicity, further research is needed to identify additional markers and uncover the cellular changes in immune cells caused by PFAS exposure.
Furthermore, to study immune cells in a laboratory environment they need to be grown in media supplemented with serum. The serum is commonly derived from animal blood which obviously raises ethical concerns but also introduces experimental variability, as animal serum contains undefined components and foreign particles that can affect reproducibility. This also hinders the studies of extracellular vesicles (EV), which are small particles used for communication and the transfer of molecular cargo, secreted from the immune cells. Unfortunately, the cells didn’t thrive in the fully animal-free media, showing that more work is needed before animal products can be completely phased out. However, the cells grew well in the EV-depleted serum media. This opens exciting future opportunities to study how PFAS might impact EVs and how it might influence cell behavior and cell signaling.

• author: Henderup, Felix
• supervisor: Kathrin Zeller; Henrik Johansson
• organization: Department of Immunotechnology
• course: KIMM05 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences; Technology and Engineering
• keywords: PFAS, per- and polyfluoroalkyl substances, Dendritic Cells, DCs, in vitro, human DC model
• language: English
• id: 9196912
• date added to LUP: 2025-06-11 11:15:18
• date last changed: 2025-06-11 11:15:18