Best fits of the multiexponential model to effector/memory T-cell data from prenatal and finite-term labeling experiments. (A) Mice were labeled prenatally and drank ²H₂O until age 16 weeks. At different time points after label cessation, the percentage of labeled DNA of splenic effector/memory CD4⁺ (left) and CD8⁺ T cells (right) was determined. Gray squares (⁠⁠) represent measurements (ie, individual mice) at different time points after labeling. Data were fitted with the multiexponential model (describing 2 subpopulations) to estimate the average turnover rate of the total cell population. (B-C) Effector/memory CD4⁺ (B) and CD8⁺ (C) T-cell labeling data from the finite-term (left) and prenatal labeling (right) experiments were simultaneously fitted with the multiexponential model to estimate the average turnover rate. Black circles (●) represent measurements (ie, individual mice) at different time points during labeling; during delabeling after 1 week of labeling (⁠⁠, gray diamonds), 4 weeks of labeling (⁠⁠, gray circles), or 8 weeks of labeling (⁠⁠, gray triangles); and during delabeling of prenatally labeled mice (⁠⁠, gray squares).