Anti-MAN2B1 (full length) polyclonal antibody

The a-mannosidase activity in human frontal gyrus, cerebrospinal fluid and plasma has been analyzed by DEAE-cellulose chromatography to investigate the origin of the alpha-mannosidase activity in cerebrospinal fluid (CSF). The profile of alpha-mannosidase isoenzymes obtained in CSF was similar to that in the frontal gyrus but different from that in human plasma. In particular the two characteristic peaks of lysosomal alpha-mannosidase, A and B, which have a pH-optimum of 4.5 and are found in human tissues, were present in both the frontal gyms and CSF. In contrast the majority of alpha-mannosidase activity in human plasma was due to the so called intermediate form, which has a pH-optimum of 5.5. The results suggest that the intermediate form of alpha-mannosidase in plasma does not cross the blood-brain barrier and that the alpha-mannosidase activity present in the cerebrospinal fluid is of lysosomal type and of brain origin. Thus the alpha-mannosidase activity in cerebrospinal fluid might mirror the brain pathological changes linked to neurodegenerative disorders such as Parkinson's disease.

Deficiency in human lysosomal alpha-mannosidase (MAN2B1) results in alpha-mannosidosis, a lysosomal storage disorder; patients present a wide range of neurological, immunological, and skeletal symptoms caused by a multisystemic accumulation of mannose-containing oligosaccharides. Here, we describe the expression of recombinant MAN2B1 both transiently in Nicotiana benthamiana leaves and in the leaves and seeds of stably transformed N. tabacum plants. After purification from tobacco leaves, the recombinant enzyme was found to be N-glycosylated and localized in vacuolar compartments. In the fresh leaves of tobacco transformants, MAN2B1 was measured at 10 200 units/kg, and the purified enzyme from these leaves had a specific activity of 32-45 U/mg. Furthermore, tobacco-produced MAN2B1 was biochemically similar to the enzyme purified from human tissues, and it was internalized and processed by alpha-mannosidosis fibroblast cells. These results strongly indicate that plants can be considered a promising expression system for the production of recombinant MAN2B1 for use in enzyme replacement therapy.