Figure 2: Immune cell infiltration in the brain after stem cell transplantation.

(a,b) Massive numbers of CD3-positive T cells (red), CD4-positive Th cells (red), CD8-positive CTL cells (red), CD11b-positive microglia/macrophages (red) and CD19-positive B cells (red) infiltrated the brains of mice with grade 3 tumours after ESC (green, a) or iPSC (green, b) transplantation. (c,d) A few CD3-positive T cells (red), CD11b-positive microglia/macrophages (red) and CD19-positive B cells (red) infiltrated in brains of mice with grade 1 tumours after ESC (green, c) or iPSC (green, d) transplantation. (e,f) These immune cells (red) were rarely detected in the brains of mice without tumour formation after iNSC (green, e) or iPSC (green, f) transplantation. Scale bar = 25 μm.