Figure 3.

Efficiency of cellular clustering efficiency by IgG subclass.

The efficiency of CD19xCD3 BsAb IgG subclasses to facilitate clustering of target cells and T cells was assessed by flow cytometry using 20 μg/mL BsAb and a 1:1 effector cell number: target cell number ratio. Cell clustering efficiency was the percentage of double-positive events (red-labeled effector T cells and violet-labeled target cells) out of a live-cell gate. Data are presented as mean ± SD of 3–5 independent experiments, normalized to the clustering percentage in the absence of BsAb per cell line and replicate. A: CD19-negative HLY-1 cells.B: CD19-positive HBL-1 target cells (low CD19 RD).C: CD19-positive Daudi target cells (high CD19 RD).Applied Fc mutations (Supplementary Table 1) have not been included in the x-axis label for better legibility. Statistical significance was analyzed by ANOVA, and level of significance of a BsAb in comparison to untreated or IgG2 σ1 is shown as: *p-value ≤ 0.05; **p-value ≤ 0.001; ***p-value <0.0001. Not shown comparisons did not reach significance.