Cell culture of mammalian thymic epithelial cells: growth, structural, and antigenic properties.

The thymus plays an important role in the maturation and differentiation of T lymphocytes. Many of its functions have been attributed to its epithelial component. Past in vitro studies of putative thymic epithelial cells have been hampered by the inability to produce well-characterized cultures of these cells. Using lethally irradiated 3T3 cells as a feeder layer, we have succeeded in growing virtually pure cultures of thymic epithelial (TE) cells from rabbits, mice, and humans. Antikeratin staining provides an unambiguous criterion for positive identification of the epithelial cells. These cells were found to lack Ia-like or theta-like antigens. The ability to culture large quantities of mammalian TE cells should allow for their detailed functional characterization.