Fig. 2

Butyrate promotes Treg differentiation and suppressive function. (A) Magnetically sorted naive CD4⁺ T cells (2 × 10⁵ cells) obtained from the peripheral blood of patients with AChR MG were cultured for 3 days under Treg-polarizing conditions using butyrate at concentrations of 0 μM, 100 μM, 200 μM and 400 μM. The frequencies of CD4⁺CD25⁺FOXP3⁺ Tregs were determined by flow cytometry. (B, C, D) Magnetically sorted CD4⁺CD25⁻ responder T cells (2 × 10⁵ cells) from patients with AChR MG were labeled with CFSE and cultured with CD4⁺CD25⁺CD127_low Tregs for 5 days in the presence of plate-bound anti-CD3 and anti-CD28, with or without 200 μM butyrate. The suppressive function of Tregs was measured by calculating the proliferation of CFSE⁺ cells (t = 18.81, p < 0.001for difference between Vehicle and Butyrate with unpaired t-test; F = 211.4, p = 0.0043 for difference between 1:1 and 1:2 with ANOVA, p = 0.0236 for difference between 1:1 and 1:4 with ANOVA). Each dot represents an individual sample. Data are shown as the mean ± SEM, * p < 0.05, ** p < 0.01, *** p < 0.001, ns = not significant