Figure 4. Potency of TSLP in inhibiting iTreg generation.

A, TSLP suppressed murine iTreg differentiation in a dose dependent manner. Naïve CD4+ T cells isolated from spleens and lymph nodes of Foxp3^eGFP mice were cultured with 5 μg/ml plate-bound anti-CD3 and 1 μg/ml anti-CD28 for 24 hours, removed from stimuli and cultured for another 9 days for Treg generation. TSLP was included in the culture at concentrations as indicated throughout 10 days of culture. Data represent mean ± SEM (n = 3) from one of three independent experiments. B, Both percentage and number of Foxp3^eGFP+ cells were reduced in response to increasing dose of TSLP. C, Specificity of TSLP in suppressing iTreg differentiation. Naïve CD4⁺ T cells were isolated from TSLPR deficient mice and cultured in the conditions as described in (A). No significant inhibition of iTreg differentiation was seen even when 20 ng/ml TSLP was included in the culture.