Characterization of in vitro T lymphocyte colonies from normal mouse spleen cells: colonies containing cytotoxic lymphocyte precursors.

The functional activity of T cell colonies grown from normal murine spleen cells has been examined. Up to 75% of the T cell colonies contain cytotoxic lymphocyte precursors (CLP). One out of three colonies contains CLP, which can respond to a given foreign H-2 haplotype. The CLP from the T cell colonies appear identical to the CLP in lymph node tissues in their degree of cross-reactivity and requirement for accessory cells. The effector cells produced were shown to be T lymphocytes. Karyotypic analysis of the cells in colonies grown from a mixture of T6-marked and normal spleen cells indicated that individual colonies were formed from an initial small aggregate of cells. Radiation survival data indicated that the colony-forming unit contains three or fewer proliferating cells.