Figure 2. Immunohistology of the Epithelium Identifies CD11c-YFP^int Cells as CD103⁺ DCs.

Samples of the small intestine from untreated mice were rapidly excised and fixed for immunohistological analysis of whole-mounted tissues. Single Z-planes are shown (scale bars represent 10 μM).

(A) In Cd11c-YFP mice, not only CD4⁺CD8⁺ IELs but also some CD11c-YFP⁺ cells (arrow) were located directly above the laminin⁺ basement membrane among enterocytes. Such cells expressed less YFP than the highly-branched cells confined to the LP.

(B) Within the epithelial layer, amoeboid YFP⁺ cells (arrows) could be seen alongside IELs.

(C) A CX₃CR1-GFP⁻CD11c-YFP⁺ cell (in yellow) in the epithelium exhibited an elaborate shape and no T cell markers

(D) YFP^int cells (arrows), located beneath and among enterocytes expressed membranal CD11c.

(E) A YFP^int cell (arrow) expresses CD11c, but not CD4 or CD8, whereas adjacent IELs do.

(F) CD103 is expressed by the large YFP⁺ cells (arrow), which do not express CD4 or CD8.

(G) CD103 and CD11c are coexpressed by a large YFP⁺ cell (arrow) in the epithelium.

(H) CX₃CR1⁻GFP⁻CD11c-YFP^int cells, marked with membranal CD103⁺, can be located in the epithelium.

(I) YFP⁺ CD11c⁺ cells were also observed in the epithelium of Rag1^−/− mice (arrows). All micrographs are representative of at least six independent samples.