(A) scRNA-Seq UMAP and (B) composition plot of mononuclear phagocytes sorted from allografts 7 days after transplantation of BALB/c hearts into CSB- (n = 3) or CSA-treated (n = 3) B6 WT mice. (C) Flow cytometry quantification of cDC1s within allografts of CSB- (n = 3) and CSA-treated (n = 3) B6 WT recipients at 7 days after transplant. (D) Immunostaining of graft-infiltrating cDCs (GFP⁺) and PDL1 in CSB- (n = 6) and CSA-treated (n = 5) B6 Zbtb46^gfp/+ recipients of BALB/c hearts at 7 days after transplant. Scale bar: 50 μm. (E) Quantification of GFP⁺ and PDL1⁺ cells in CSB- (n = 6) and CSA-treated (n = 5) allografts at 7 days after transplant into B6 Zbtb46^gfp/+ mice. (F) Kaplan-Meier survival curves of BALB/c hearts after transplantation into CSB-treated B6 WT, Δ1+2+3, and Irf8+32^–/– mice (n = 10 per condition). (G) Histology (H&E, Verhoeff-Van Gieson elastin stain) of allografts from B6 WT, Δ1+2+3, and Irf8+32^–/– recipients at 60 days after transplant (WT, Δ1+2+3) or time of rejection (Irf8+32^–/–). Fractions in the top right corner indicate the number of samples with histology matching the representative image out of the total samples in each cohort. Scale bar: 50 μm (top); 20 μm (bottom). (H) Immunostaining of CD4⁺ and CD8⁺ T cells in allografts of B6 Irf8+32^–/– (n = 3) and WT (n = 3) recipients at 14 days after transplant. Scale bar: 50 μm. (I) scRNA-Seq UMAP and (J) composition plot of subclustered T cells B6 WT (n = 3) and Irf8+32^–/– (n = 3) recipients. (K) Pathway analysis of genes differentially expressed in T cells.