Jak3^KI/KIT cells are sensitive to the JAK3 inhibitor tofacitinib. (A) Representative western blot showing the efficacy of a 6-hour treatment with tofacitinib on Jak3^KI/KI splenocytes. Representative values of band intensity relative to DMSO are indicated. (B) Dose-response curves of tofacitinib treatment over 3 days for KI/KI cell survival in vitro. Data are mean ± SEM. P values are shown (Student t test). (C) Comparison of the sensitivity of CTCL-like Jak3^KI/KI, Ts1Rhr-Jak3^KI/KI, CD4⁺ Ts1Rhr-Jak3^KI/KI, and T-ALL Ts1Rhr-Jak3^KI/KI to tofacitinib treatment. Mean ± SEM from 2 to 5 mice per group (each in triplicates) is indicated. P values are indicated.