Analysis of cytolytic T lymphocyte precursors in normal and regenerating thymus: Correlation between surface phenotype and function as revealed by flow microfluorometry

By combining flow microfluorometric analysis of thymocytes stained with monoclonal antibodies directed against Lyt-2, H-2K and Thy-1.2 with a quantitative assay for cytolytic T lymphocytes precursors (CTL-P), the cell surface phenotype of thymic CTL-P was found to be Lyt-2⁺, H-2K(b)-positive and Thy-1-weak. As such, thymic CTL-P are contained in a 'mature' subpopulation of cells phenotypically indistinguishable from cortisone-resistant thymocytes. In AKR→CBA radiation bone marrow chimeras the host-derived (CBA) subpopulation of thymocytes, present during the early stages of thymic regeneration, contained CTL-P at a frequency similar to that of normal adult CBA thymocytes.