3T3

3T3 refers to a family of mouse fibroblast cell lines derived from embryonic tissue, most notably the Swiss 3T3 line. The name originates from the original culture protocol in which cells were dissociated and re-plated at a defined density every three days, yielding the first 3T3 lines described by Todaro and Green in 1962. Over time, several substrains and derivatives have been developed from the original line.

These cells are adherent, fibroblast-like cells that grow as monolayers and exhibit contact inhibition under normal conditions. They are typically maintained in standard mammalian cell culture media supplemented with serum and incubated at 37°C in a suitable CO2 atmosphere. The 3T3 lineage is prized for its robustness and ease of use in laboratory settings.

Applications and significance: 3T3 cells have been central to cancer biology, toxicology, and cell signaling research. The NIH/3T3 and BALB/c/3T3 variants are commonly used in transformation assays to detect oncogenic activity, assess DNA transfection efficiency, and study cellular responses to growth factors. A derivative line, 3T3-L1, is a preadipocyte model frequently used to study adipogenesis. Other substrains, such as 3T3-J2, are employed in specialized co-culture systems, including keratinocyte-dermal fibroblast models.

Origin and scope: Swiss 3T3 lines were established in the early 1960s from mouse embryos, and the 3T3 designation has become a general label for related substrains used widely in biomedical research. Despite the availability of other models, 3T3 cells remain a foundational tool for exploring basic cell biology and transformation phenomena.