Characterization of in vitro T-lymphocyte colonies from spleens of nude mice.

Cells residing in the spleens of nude mice that appear Thy-1 negative can give rise to Thy-1 positive colonies in an in vitro culture system. Cells from pooled colonies can provide an accessory cell required for the development of cytotoxic lymphocytes from their precursors in an in vitro mixed lymphocyte reaction. As few as 50 such colony cells produce detectable activity.