Figure 2.

Immune‐tolerant transgenic alpha‐mannosidosis mice are phenotypically indistinguishable from nontransgenic animals. (A) Separation of neutral oligosaccharides extracted from brains of 3‐4 months old wild‐type (+/+), nontransgenic (‐/‐) and transgenic (‐/‐ +tg) mice by TLC shows comparable amounts of all glycan species (Man₂–Man₉). (B) Quantitative analysis of oligosaccharides by high pressure liquid chromatography indicate equal levels of the major glycan species Man₂ and Man₃ (n = 3‐4, per genotype). (C) α‐glucuronidase, β‐hexosaminidase and α‐galactosidase show a similar increase in their specific activity in brain extracts of nontransgenic and transgenic knockout mice compared to wild‐type animals (n = 3, per genotype). (D) Light microscopy of Toluidine‐stained semithin sections from the ganglion (G.) trigeminale, hippocampus and cerebellum reveals similar amount of storage vacuoles in both knockout strains. Scale bar: 50 μm, insets show zoomed images of the outlined area; stars (*) highlight vacuolated storage cells. (E) Immunofluorescence labeling of LAMP‐1 revealed a similar increase in LAMP‐1 levels in ‐/‐ and ‐/‐ tg+ mice compared to +/+ animals in the hippocampus, cerebellum and the cerebral cortex (Scale bar: 50 μm). (F) Reactive microglia (green) are present to a similar degree in the molecular layer of the cerebellum of ‐/‐ and ‐/‐ tg+ mice (4’,6‐Diamidin‐2‐phenylindol (DAPI), blue; Scale bar: 50 μm) (*P < 0.05, **P < 0.01, ***P < 0.001). TLC, thin layer chromatography; LAMP‐1, Lysosome‐associated membrane glycoprotein 1.