Abstract
Thymocytes were separated according to their surface phenotype and tested for cytotoxic T lymphocyte (CTL) precursor function by stimulation with allogeneic or hapten-coupled cells, with or without addition of T cell growth factor (interleukin 2). The data show that only a minor subpopulation of thymocytes agglutinated by peanut agglutinin, expressing relatively high amounts of H-2K antigen, contained CTL precursors. The remaining population, approximately 80%, could not be induced to generate CTL, even in the presence of interleukin 2.