Absolute values of thymocyte subpopulations, as defined by CD3/CD4/CD8 triple-labeling, found in control or irradiated mice. For simplification, CD4/CD8-defined thymocyte subsets were divided into −/lo or in/hi according to their level of CD3 expression. For examples for this arbitrary CD3 division, see Figs 12 and 13. Values were obtained with the labeling of pooled thymocytes from at least three animals per point.