Figure 1

Immunostained first sections and 3D models of R1 to R3 showing the location of capillary sheaths First section of R1 (a), R2 (c) and R3 (e) stained for CD34 plus SMA in brown and CD271 in blue. The first sections are compared to the 3D-model of R1 (b), R2 (d) and R3 (f) showing staining for CD34 plus SMA in yellow, for post-arteriolar CD271⁺ capillary sheaths in green and for capillary sheaths of undetectable location in blue. CD271⁺ FDCs in follicles are also blue. The direct connections of arterial vessels to green sheaths were manually marked in red. The iso-values were chosen to exclude weakly CD34⁺ perifollicular sinus endothelia and weakly CD271⁺ interstitial fibroblasts without compromising microvesssel continuity. As a consequence of this, the diameter of microvessels differs among the ROIs. Scale bars = 100 µm, f = follicle, t = trabecula, tv = trabecular vein.