Absence of lymphoid reconstitution in mice injected with infected CD11c⁺ cells. (a–d) Hematoxylin and eosin staining of paraformaldehyde-fixed sections at the same magnification. ×25. A normal lymphoid architecture of the spleen is found in RAG1^0/0 mice that had been injected with live total spleen cells (a) and the B cell–enriched fraction (b), but not in RAG1^0/0 mice injected with killed spleen cells (c) or the live CD11c⁺ cell–enriched fraction (d). (e and f) Higher magnification (×1,000) of lymphoid follicles in spleens from mice injected with total spleen cells (e) reveals typical aspect including immunoblasts and centroblast, which is clearly different from that of nodules found in spleens from CD11C⁺ cell–injected mice (f); the latter are made of smaller cells, essentially with a nonlymphoid morphology and likely belonging to other hematopoietic lineages. (g and h) Frozen sections from spleens of RAG1^0/0 mouse recipients injected with total spleen cells (g; ×400) or the CD11c⁺ cell–enriched fraction (h; ×400) were triple stained with anti-CD3-FITC (green), anti-CD19-phycoerythrin (red), and anti-CD11c-Cychrome5 (blue). The absence of lymphoid structure in RAG1^0/0 mice injected with CD11c⁺ cells is confirmed on h, which is representative of the entire spleen and shows no staining for B (CD19) and T (CD3) cells. (i and j) Immunohistochemical evidence of PrP^Sc (see Methods) accumulation in spleens from RAG1^0/0 mice infected with total spleen cells (i; ×200) but not in those from mice infected with the CD11c⁺ cell–enriched fraction (j; ×200).