Spontaneous cytotoxic T cells in murine spleen-cell cultures. I. Some characteristics of effector and precursor cells.

Cytotoxic T cells that arise spontaneously in culture (SCTL) have been characterized using a sensitive plaque reduction (PR) assay. Although SCTL effector cells are highly susceptible to anti-Thy-1 antibody plus complement treatment, they are derived from precursor cells having very low levels of Thy-1 antigen. SCTL are barely detectable in cultures of thymus cells, bone marrow cells, and spleen cells from athymic nu/nu and very old mice. Since SCTL have some similarities to both natural killer cells and normal cytotoxic T cells, SCTL may represent a stage in the T-cell lineage that links these two forms of cytotoxicity.