tLNs are anatomically normal. Three to 4 weeks after engraftment of syngenic LNs to C57BL/6 ear pinnae, tLNs were harvested and sectioned for immunofluorescent staining. (A) Confocal imaging of control and tLN showed equivalent BP3⁺ stromal cell (green) staining. CD4⁺ (blue) and IgM⁺ (red) staining allows T- and B-cell areas to be visualized for reference. Scale bars represent 50 μm. (B) Segregation of T cells and B cells was also evidenced by compartmentalization of CD4⁺ (green) T cell and IgM⁺ B cell (red) staining. Images shown are representative of 3 replicate mice; scale bars represent 100 μm. (C) tLNs were excised from the recipient animals, and single cell suspensions were made. Cells were then stained for B220, CD8, and CD4, and expression levels were determined by flow cytometry. These were compared directly to control, non-tLNs. The proportions of CD4⁺, CD8⁺T cells, and B220⁺ B cells in the tLN were found to be comparable with the control. Data show 6 replicate mice per group (see supplemental Figure 2 for representative plots and gating strategies).