An immunoelectron microscopic study of glucocerebrosidase in type 1 Gaucher's disease spleen.

An immunogold labeling procedure was applied to ultrathin cryosections and used to study the subcellular localization of glucocerebrosidase in lipid-laden "Gaucher cells" in spleen from a patient with type 1 Gaucher's disease. Glucocerebrosidase protein was associated with the characteristic stored lipid material in large, irregularly shaped vacuoles. As shown by double labeling, the storage vacuoles contained not only glucocerebrosidase protein but also other lysosomal enzymes. Thus the storage vacuoles can be considered to be secondary lysosomes. The findings indicate that although glucocerebrosidase was present in secondary lysosomes in this patient, the activity of the mutant enzyme was insufficient to prevent storage of glucocerebroside in the spleen.