title: Presynaptic membrane receptor in human brain.
abstract: Myasthenia gravis (MG) is an autoimmune disease that results from antibody mediated damage of Acetylcholine receptor (AChR) at the neuromuscular junction. The autoimmune character of MG and pathogenic role of AChR antibodies have been established by several workers i.e., the demonstration of anti-AChR antibodies in about 90 % of MG patients. It has been demonstrated that patients with MG also have antibodies against a second protein named presynaptic membrane receptor (PsmR), which is identified by utilizing β-Bgtx, a ligand which binds to PsmR. Using β-Bgtx Sepharose 4B affinity matrix, the PsmR was purified from different regions of human cadaver brain by affinity chromatography. Purified receptor was characterized both by biochemical and immunological procedures. PsmR purified from different regions of the brain shows a specific activity of 0.37 ± 0.01, 0.39 ± 0.02 and 0.43 ± 0.005 nM/ μg of protein in Parietal lobe, Occipital lobe and Frontal lobe respectively. The affinity purified PsmR from the brain of 87 and 68 kd (parietal lobe, occipital lobe and frontal lobe) shows immunoreactivity with myasthenic sera. These findings suggest that PsmR from brain is another antigen against which autoantibodies are developed in Myasthenia gravis patients. Upon treatment with various enzymes we concluded that PsmR from brain is a glycoprotein in which the immunoreactivity resides in the carbohydrate as well as the peptide epitopes. In conclusion the PsmR is another antigen against which autoantibodies are formed in different regions of brain. These can be used as a diagnostic tool for detecting antibodies in the sera or cerebrospinal fluid of MG patients.
authors.affiliation: Department of Physiology and Neursociences MSB 453, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 USA.
authors.forename: Suhail
authors.initials: S
authors.lastname: Rasool
authors.affiliation: Department of Neurology, Neurosciences Center, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029 India.
authors.forename: Madhuri
authors.initials: M
authors.lastname: Behari
authors.affiliation: Department of Neurology, Neurosciences Center, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029 India.
authors.forename: Vinay
authors.initials: V
authors.lastname: Goyal
authors.affiliation: Department of Laboratory Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029 India.
authors.forename: Mohd
authors.initials: M
authors.lastname: Irshad
authors.affiliation: North East Region-Biotechnology Programme Management Cell (NER-BPMC; DBT.GOVT of India), A-254 Bhisham Pitamah Marg, Defence Colony, New Delhi, 110024 India.
authors.forename: Bansi Lal
authors.initials: BL
authors.lastname: Jailkhani
keywords: Human cadaver brain; Presynaptic membrane receptor; β-Bgtx and purification