Establishment and characterization of a thymic medullary epithelial cell clone.

Thymic stromal cells were cultured in conditions which select for epithelial cells. These were then transformed in vitro by contact with N-methyl-N'-nitro-N-nitrosoguanidine and cloned at limit dilution. One of the clones was characterized as being of medullary origin on the basis of its reactivity with a battery of antibodies previously shown to distinguish cortical from medullary thymic epithelial cells. The importance of this clone lies in the potential it offers to delineate how various T cell subpopulations acquire their distinct markers and function within the thymus.