The nature of mannose-containing material which accumulates in cultured fibroblasts from patients with mannosidosis

High-resolution loading tests in the study of genetic heterogeneity in gangliosidosis fibroblasts

GM1- and GM2-gangliosides were isolated from brain and radiolabelled. The labelled moieties were localized by hydrolysis with lysosomal enzymes, followed by thin-layer chromatography of the products. High-resolution loading tests with labelled gangliosides were developed and found to differentiate infantile and juvenile forms of GM1- and GM2-gangliosidoses as well as the identification of B, O and AB types of GM2-gangliosidosis.

Direct enzyme transfer from lymphocytes corrects a lysosomal storage disease

Fibroblasts from patients with mannosidosis, the lysosomal storage disease resulting from an inherited deficiency of lysosomal alpha-D-mannosidase (EC 3.2.1.24), accumulate specific mannose-containing oligosaccharides which are characteristic of the disease (1,2). The present study shows that these substances were extensively degraded following transfer of the missing enzyme from normal lymphocytes to mannosidosis fibroblasts on direct contact in tissue culture. Moreover, prolonged correction of the metabolic abnormality of the recipient cells was sustained if contact with fresh donor lymphocytes was periodically renewed. These findings may be highly relevant to lymphocyte function in enzyme replacement therapy by transplantation procedures currently being attempted.