CD4 SP thymocytes, but not Treg cells, store and mobilize pCD40L.

A, Gating strategy for thymic nTreg cells and CD4 SP thymocytes. B, Generation of in vivo iTreg cells. DO11.10 CD4⁺ T cells were recovered from OVA- or BSA-fed recipient mice on day 6. C, Gating strategy for in vivo iTreg cells and effector CD4⁺ T cells. A BSA-fed mouse is shown as a negative control. D, thymic nTreg cells; E, CD4 SP thymocytes; F, in vivo iTreg cells; and G, effector CD4⁺ T cells, are analyzed by the mobilization assay and intracellular staining for pCD40L and CTLA-4. Data are representative of three (D and E) or two (F and G) independent experiments.