High Thymic Output of Effector CD4⁺ Cells May Lead to a Treg : T Effector Imbalance in the Periphery in NOD Mice

Figure 8

Percentages of CD4⁺ recent thymus emigrants (RTE) that are Foxp3⁺ are lower in NOD compared to B6 mice at 9 weeks of age and may be due to the higher rate of thymic output of CD4⁺Foxp3^- cells in NOD mice. Both thymic lobes of NOD and B6 mice were injected with 10 μl of either (a) PBS (upper left panel) or FITC (upper center panel) at 4, 7, or (a) 9 weeks of age. This typically resulted in random labeling of 20-40% of the thymocyte population. Mice were sacrificed 24 hours after injection, and lymphoid organs (LN and spleen) were collected. FITC⁺CD4⁺ cells (RTE) in secondary lymphoid organs were gated (a, lower center panel) and analyzed for the percentages of Foxp3⁺ (a, upper panel right, and b). (c, d) The daily (24 h) thymic export rates of CD4⁺Foxp3⁺ (c) or CD4⁺Foxp3^- (d) cells in 9-week-old mice were determined using the formula described in Methods. denotes a significant difference at .

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