Fig 3.

Lack of BM-derived ALPP⁺ epithelial cells in irradiated wt F344 rats reconstituted with unfractionated BM from ALPP-tg F344 donors. Histochemical detection of ALPP enzyme activity (BCIP/NBT, purple) reveals absence of BM-derived epithelial cells in gut (A), kidney tubules (B), liver (C), or skin (D), 6 months after BMT. (E) Co-staining of ALPP enzyme activity (blue) and anti-CD68 antibody (purple) in lung sections shows many double positive alveolar macrophages (centre), but also some CD68⁺ ALPP^– macrophages as indicated by arrows, 4 months after BMT. Double staining of ALPP enzyme activity (blue) with anti-insulin (F), anti-somatostatin (G) or anti-pancreatic polypeptide (H) (purple) demonstrates lack of BM-derived endocrine cells in islets of Langerhans. The paraffin sections shown in (A–D) were stained for ALPP enzyme activity with BCIP/NBT (purple) overnight at RT after heat pre-treatment, and were counterstained with nuclear fast red. The paraffin sections in (E–H) were stained for ALPP enzyme activity using Vector Blue, and immunostained against CD68, insulin, somatostatin, or pancreatic polypeptide using Vector VIP (purple) as substrate. Bars represent 50 μm.