Thymic subsets. Flow cytometric analysis of the thymocyte subsets at time of necropsy in the 3 different groups. SP indicates single-positive (CD4⁺ or CD8⁺); DP, double-positive (CD4⁺ CD8⁺); DN, double-negative (CD4⁻CD8⁻). The thymus of animals CJ5D and RQ3564 were not available for this analysis.