MeT-5A Cells

MeT-5A is a laboratory cell line of human mesothelial cells, the same type of cells that line the chest and abdominal cavities and that give rise to mesothelioma. The cells were taken from a healthy donor and immortalized in the lab so they can grow continuously, giving researchers a stable, non-cancerous mesothelial cell to study. Scientists use MeT-5A cells to investigate how asbestos fibers injure normal mesothelial tissue and trigger the changes that lead to cancer.

Origin

The MeT-5A line was established in the late 1980s by researchers who collected mesothelial cells from a non-diseased human donor and immortalized them by introducing the SV40 virus early-region genes. It is deposited in the American Type Culture Collection (ATCC) and has since become one of the most widely used reference lines for normal human mesothelium in asbestos research.

Significance in Asbestos Context

MeT-5A cells are a foundational tool behind much of what is now known about how asbestos causes mesothelioma. Experiments exposing MeT-5A cells to crocidolite, amosite, and chrysotile fibers have shown DNA damage, chromosomal breakage, oxidative stress, chronic inflammation, and activation of cancer-related pathways at exposure levels relevant to human disease. This kind of mechanistic evidence is frequently cited by experts to explain to courts and juries how even relatively low fiber exposures can initiate the biological cascade that ends in mesothelioma decades later. When defendants argue that a particular fiber type or dose is too low to cause disease, plaintiff experts often point to MeT-5A and similar cell-line studies as direct laboratory evidence that the fibers do, in fact, damage normal human mesothelial cells.

Example Sentence

The plaintiff's cellular biology expert cited a series of MeT-5A studies showing that chrysotile fibers caused the same DNA double-strand breaks and inflammatory signaling as amphibole fibers, undercutting the defendant's claim that chrysotile is biologically inert.

Related Terms

Mesothelial Cells, Genotoxicity, Oxidative Stress, Chrysotile, Crocidolite, In Vitro Studies

Notes

• If your case involves disputes about whether a specific fiber type (especially chrysotile) can cause mesothelioma, ask your legal team whether their experts rely on MeT-5A or similar normal mesothelial cell studies to demonstrate biological plausibility.
• MeT-5A is a non-cancerous cell line; it is distinct from mesothelioma cell lines (such as H2452 or MSTO-211H) that are used to study existing tumors. Make sure expert reports in your case distinguish which type of cell line supports which conclusion.
• Because MeT-5A was immortalized with SV40, some defense experts argue findings cannot be extrapolated to human disease; ask whether your experts also cite confirmatory data from primary (non-immortalized) human mesothelial cells or from animal and human tissue studies.