The CD3×CD3 BsAb depletes human T cells in vivo. NSG mice were injected with 30 million PBMCs IP. Peripheral blood was stained for the presence of T cells on day 7 and treatment was started the day after. Treatment was composed of IV injection of 1 μg or 0.1 μg CD3×CD3 or a CD19×CD3 BsAb. (A) At different time points, blood was taken and stained for the presence of human cells. The number of human CD45 cells (B), CD4 (C), and CD8 (D) T cells was determined using flow cytometry. Area under the curve was compared between groups using ANOVA and multiple comparison analysis. n = 5 mice per group.