Figure 4: p210-cBSA inhibition of T cell proliferation is dependent on DCs but independent of antigen specific T effector cells and presence of Tregs. The direct effect of p210-cBSA on T effector cell proliferation was measured using CD3/CD28 beads in the presence or absence of p210-cBSA (A). Proliferation of polyclonally activated T effector cells was determined using DCs, Tregs and T effector cells from OTII mice after incubation with p210-cBSA (B). T effector cell proliferation with p210-cBSA, cBSA or p210 was assessed in the absence of Tregs and in the presence of DCs (C). The proliferative capacity of the cells is expressed as counts per minute (CPM) and un-stimulated cells served as control. The ability of p210-cBSA to induce conversion of naïve T effector cells into Tregs was studied by pulsing DCs with p210-cBSA (p210DCs) for two hours and then analyzing the frequency of Tregs with flow cytometry after 72 hours coculture. Tregs were induced in the absence (D) and presence (E) of IL-2 and TGF-β and un-stimulated cells served as controls (cDCs). Tregs were gated as CD25+FoxP3+ out of CD3+CD4+ cells. (*p ≤ 0.05, **p ≤ 0,01 ,***p<0.001).