Figure 5.

Development of a melanoma model in humanized NSG-SGM3 mice. (A) Neonatal NSG-SGM3 mice were treated with 1 Gy irradiation before intrahepatic injection of human CD34⁺ cells. Eight weeks later, human chimerism in peripheral blood was confirmed with flow cytometry. Mice were then injected subcutaneously with the patient-derived melanoma cell line LM-MEL28 before treatment with Flt3L, PolyIC and/or pembrolizumab (immunotherapy). (B) Human immune populations in spleens of humanized (hu) NSG-SGM3 mice at 12 weeks post engraftment showing identification of DC subtypes (n=5–6 mice per group). (C) Proportions of human immune lineages in spleens of non-treated huNSG-SGM3 mice±subcutaneous LM-MEL28 tumors (n=5 tumor-bearing, 3 non-tumor-bearing mice). (D) Infiltration of human CD45⁺ leukocytes in LM-MEL28 tumors in vivo, a representative gating strategy is shown on the left and percentages of each subset within the total human CD45⁺ cells (mean±SEM, n=9 mice) shown on the right. (E) NSG-SGM3 mice injected with human CD34⁺ cells (‘engrafted’) were injected with melanoma cells alongside age-matched non-engrafted mice. Tumor growth curves and tumor weights (excised at day 35) are shown; no significant difference between groups was observed using Student’s t-test (n=5–6 mice per group).