Figure 3.
PD-1 x CTLA-4 Bispecific Inhibitor Enhances T Cell Activation
(A) Dual reporter cell line (Jurkat-PD-1/CTLA-4 cells) and artificial APCs (Raji-PD-L1/B7 cells) were co-cultured in the presence of MGD019 (red diamonds), its parental PD-1 (blue squares) or CTLA-4 (green triangles) mAbs, their combination (purple crosses), nivolumab33 ( blue blue crosses), ipilimumab (yellow triangles), or their combination (tan hexagons) and isotype control (black circles). Representative experiments out of 3 independent repeats are shown.
(B) Mean fold change of IL-2 concentrations in the samples treated with 10 μg/mL of MGD019 or control mAbs relative to samples treated with control IgG plus indicated concentrations of SEB. The experiments were performed individually with PBMCs from healthy donors (N = 39). Error bars depict SEMs. Inset: subset of donors (N = 9/39) with reduced effects to PD-1 blockade (IL-2 fold change [f.c.] < 2) demonstrate enhanced responses to MGD019; 25 ng SEB dose is shown. Mean values are shown. Paired t-test with two tailed p value calculation was used.
(C) PBMCs from healthy donors were activated in vitro with anti-CD3 and treated with MGD019 or replicas of ipilimumab featuring its original IgG1 Fc or replaced with IgG4. Fraction of FoxP3+ T cells was measured after 48-h incubation. Representative graphs of 18 independent replicates are shown.
(D) Mean values of CD4+FoxP3+ cells measurements across multiple (N = 6) independent repeats using PBMCs of different donors (N = 2).
See also Figure S4.