FIGURE 5 from Siglec-15 Promotes Evasion of Adaptive Immunity in B-cell Acute Lymphoblastic Leukemia

Sig15 is required for adaptive immune escape in murine B-ALL. qRT-PCR shows genetic knockdown of Siglec15 expression in a murine model of B-ALL by shRNA (shSig15; A) or knocked out using CRISPR/Cas9 (Sig15 KO; B). Data are normalized to the expression levels of a non-silencing vector control (shNS) or Cas9-expressing cells without gRNA (Cas9). C and D, Unirradiated WT or Rag1^−/− C57BL6 mice were injected via tail vein with 5 × 10⁵ control or Sig15-deficient leukemia cells. Luciferase signal over time represents disease burden as measured via IVIS imaging over 14 days. Kaplan–Meier curve shows prolonged survival of WT recipients of Sig15-deficient leukemia. E,P < 0.0001; shNS WT versus shSig15 WT, Mantel–Cox log-rank test; n = 10 per group from two independent experiments. F,P < 0.0001, Cas9-only WT versus Sig15 KO WT; n = 10 per group from two independent experiments.