B-NDG mice engrafted with CD34+ HSC cells were used forin vivo efficacy assessment. Mice were treated with anti-human PD-1 antibody Pembrolizumab or anti-CD20 antibody Rituximab after Raji-Luc cell implantation. Dramatic tumor growth inhibition by both Pembrolizumab and Rituximab was observed.
Figure 1. Establishment of human PBMC engrafted GvHD model in B-NDG mice.
B-NDG mice (female, 8-week old, n=5) were engrafted with 10 million human PBMC from two donors (D1, D2) on day 0. PBMC from donor 2 demonstrated more robust GvHD than those from donor 1. GvHD were scored according to Table 1.
免疫チェックポイント阻害剤によるRKO / B-NDGマウスのGvHDの悪化
B-NDG mice (female, 8-week old, n=5) bearing RKO tumor (5 million, 50% Matrigel, inoculated subcutaneously on day 4) were engrafted with 10 million human PBMC from two donors (D1, D2) on day 0. Treatment by 125 ug per mouse pembrolizumab and ipilimumab, BIW, i.p. started on day 14. Checkpoint inhibition resulted in earlier onset and more severe GvHD, with more prominent effects with PBMC from donor 2, which had more robust GvHD than PBMC from donor 1. GvHD scores are shown in top panels and body weight (BW) changes in low panels. GvHD was scored according to Table 1.
Figure 3. Pharmacological validation of GvHD model in B-NDG mice: alleviation of GvHD by corticosteroid drug.
B-NDG mice (female, 8-week old, n=7-8) were engrafted with 20 million human PBMC (iv) on day 0. Drug treatment (i.m., qdx4) started on day 7. Robust GvHD developed in the absence of treatment. Corticosteroid drug dose-dependently controlled the disease. High dose (1 mg/kg) of the drug GvHD resulted in delayed onset and reduced severity of symptoms while low dose (0.1 mg/kg) of the drug led to intermediated effect. GvHD was scored according to Table 1.
PBMC移植RKO / B-NDGモデルで、免疫チェックポイント抑制剤の強い抗腫瘍効果が見られました。
Figure 1. Checkpoint inhibitors showed encouraging anti-tumor activity in PBMC engrafted RKO/B-NDG model.
B-NDG mice (female, 8-week old, n=4-5) were engrafted with 10 million human PBMC (iv) and 5 M RKO cells (in 50% Matrigel, inoculated subcutaneously) according to Panel A. Tumor volume (B-D) and body weight (E) were monitored over time. Percent of human CD45 cells in total human and mouse CD45 cells in terminal bleeds were indicated (C, D). Data were expressed as mean +/- SEM. TGI: tumor growth inhibition. Pembro/ipi: pembrolizumab/ipilimumab.
PBMC移植RKO / B-NDGモデルでは、免疫チェックポイント抑制剤で治療の後、血液中のCD8細胞の数及びCD8/Treg比率が著しく上昇します。
Flow cytometry analysis of terminal blood (A,B) and tumor (C, D) samples were performed. A dichotomy of responders vs non-responders to checkpoint inhibition was observed in tumor and blood. Blue circles: poor (<1%) human PBMC engraftment; green and magenta circles: responders and non-responders in Figure 2C, respectively.
RKO / B-NDGでGvHDモデルの構築
Figure 3. GvHD and body weight (BW) of RKO-bearing B-NDG mice. GvHD were scored according to Table 1.