Feasibility Study of Anti-Neurofilament Antibodies Detection by Indirect Quenching Fluoroimmunoassay

Background: neurofilaments (nfs) are the main constitutes of intermediate filaments in neurons. they are composed of three subunits with heavey, medium and low molecular weight. anti-neurofilament antibodies exist in serum of patients with some neurodegenerative diseases. materials and methods: a fluoroimmunoassay has been developed for determining of antibodies against neurofilaments, using an anti-fluorescein serum and fluorescein-labeled nfs. antibodies raised against bovine spinal cord nfs in rabbit and the labeled nfs are incubated with anti-fluorescein serum at room temperature. results: at high levels, binding of anti-neurofilaments (anti-nfs) to labeled nfs prevented subsequent binding of the anti-fluorescein to fluorescein groups, resulting in little change in the signals of the label. conversely, at low level of anti-nfs the free fraction of the labeled nfs is available to be bound by anti-fluorescein, which markedly reduced fluorescence intensity of label. thus, the fluorescence intensity of assay mixture directly reflects the amount of anti-nfs antibodies in the serum.conclusion: it is concluded that the availability of fluorescein-labeled nfs and antibody directed against fluorescein group permit measurement of anti-nfs antibodies in serum of neurodegenerative patients.