Figure 6
TL1A directly costimulates regulatory T (Treg) cell proliferation. (a) Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of purified soluble recombinant TL1A (sTL1A) confirms the predicted molecular mass of the recombinant fusion protein. (b) Wild-type (wt) or death receptor 3 (DR3)-deficient (DR3 KO) magnetically isolated CD4+CD25+ T cells (purity ≥95%) were stimulated in the presence of irradiated DR3 KO antigen-presenting cells (APCs) with anti-CD3 or anti-CD3/CD28. Where indicated, sTL1A was added and proliferation was determined at 72 h by 3H-thymidine (3H-TdR) incorporation. (c, d) sTL1A costimulates Foxp3+ Treg cells. (c) Dot-plots of Foxp3+ Treg cells from Foxp3–GFP knock-in mice pre- and post-cell sorting (purity ≥99.5%). (d) Foxp3+ Treg cells were stimulated in the presence of irradiated DR3 KO APCs with anti-CD3 or anti-CD3/CD28 and where indicated sTL1A was added. Bars represent the mean±s.e. of triplicate cultures. The results are representative of two independent experiments.
