Fig 1. Humanized mice models and efficacy evaluation of bispecific antibody. The humanized model was validated for the efficacy evaluation of bispecific antibodies. A-B: Strain-specific CD3E expression analysis in B-hCD3E and B-hCD3EDG mice by flow cytometry. Mouse CD3E was exclusively detectable in WT mice; human CD3E was exclusively detectable in homozygous B-hCD3E or B-hCD3EDG but not WT mice. C: Strain-specific PD1 and PD-L1 expression analysis in homozygous B-hPD-1/hPD-L1 mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hPD-1/hPD-L1 (H/H) mice stimulated with anti-CD3ε in vivo. Mouse PD-1 and PD-L1 were exclusively detectable in WT mice, while human PD-1 and PD-L1 were exclusively detectable in homozygous B-hPD-1/hPD-L1 mice but not in WT mice. D-E: Efficacy evaluation of CD3-based bispecific antibodies in humanized models. A high dose of Blinatumomab or BsAb X significantly inhibited tumor growth in B-hCD3E mice models inoculated with hCD19-MC38 cells (C) or in BhCD3EDG mice models inoculated with target-humanized-MC38 cells (D). F: B-hPD1/hPD-L1 humanized mice were subcutaneously implanted with MC38-hPD-L1 cells (5×105). Tested PD-1/PD-L1 BsAbs or IBI318 were inhibited significantly tumor growth to varying degrees .
Efficacy Evaluation of Bispecific Antibody Based on Human Immune System Reconstitution Models
Fig 2. Efficacy evaluation of bispecific antibody on human immune system reconstitution models.A: Human immune system reconstitution models for CD3-based bispecific antibody study. NUGC4 cells (5×106) were subcutaneously implanted after human PBMCs (5×106) were intravenously implanted into B-NDG mice. Anti-human CD3×Claudin18.2 bispecific antibody (AMG 910 analog) inhibited significantly NUGC4 tumor growth in human PBMC reconstituted B-NDG mice. B: B-NDG B2m mice plus reconstituted with PBMCs were used for anti-PD-1×PD-L1 bispecific antibody efficacy studies. Human RKO cells (5×106) were subcutaneously implanted after human PBMCs (5×106) were implanted into B-NDG B2m mice. A high dose of IBI318 (antihuman PD-1×PD-L1 bispecific antibody) inhibited significantly RKO tumor growth.
Fig 3. Cell-based function study for CD3-based bispecific antibody.A: Blinatumomab significantly promoted the proliferation of T cells co-cultured with Daudi cells in a dose-dependent manner. B: Blinatumomab showed significantly cytotoxic efficacy in a dose-dependent manner at a 10:1 ratio of Daudi to T cells. C-D: Blinatumomab increased significantly the secretion of IFN-γ and IL-2 in a dose-dependent manner.