FIGURE 4.

AL008 promotes T cell function and shows no evidence of depletion. (A) Human monocyte-derived dendritic cells were treated with 10 μg/ml AL008, anti-CD47, or isotype control and cocultured with CFSE-labeled allogeneic CD3⁺ T cells. Proliferating T cells were measured 6 d later by flow cytometry gating on CFSE-low CD3⁺ T cells. (B) Ten distinct healthy donors were tested in the conditions described in (A). Each symbol represents a different dendritic cell–T cell reaction. A paired Student t test was performed. **p < 0.01, **** p < 0.0001. The dashed line represents the median value of isotype-treated cells. (C) An ADCC assay was performed using PBMCs from two to six healthy donors. PBMCs were incubated with 200 ng/ml IL-2 overnight, then cells were harvested and incubated with 20 μg/ml AL008, anti-CD47 IgG4, anti-CD52 IgG1, or isotype control for overnight. The remaining cells were stained for monocytes (CD14; left panel), T cells (CD3; right panel), and B cells (CD20; data not shown) and cell counts obtained. For each donor, cell counts were normalized to the isotype control condition. (D) An ADCP assay was established using monocyte-derived macrophages, as previously described. Combinations of AL008 with anti–PD-1 and anti–PD-L1 were tested. For (C) and (D), a paired Student t test was done. **p < 0.01, *** p < 0.001.