Analysis of Humoral Immune Response Against to Neurofilament-H Protein in Patients with Glaucoma

Abstract

Abstract: : Purpose: To identify retinal proteins involved in autoimmune response that may cause the development of glaucomatous optic neuropathy. Methods: SEREX (serological analysis of recombinant cDNA expression libraries) method was applied for immunoscreening of rat retina cDNA expression library with serum samples obtained from patients with normal tension glaucoma. Immunoreactive phage clones were subjected to in vivo excision of pBluescript phagemids using the ExAssist helper phage/SOLR strain systems. Plasmid DNAs were purified using ABI Prism Miniprep Kits. cDNA inserts were sequenced using an ABI Prism automated DNA sequencer and sequence alignments were performed using BLAST software. Subsequently, we evaluated the titer of IgG autoantibody in sera by using enzyme-linked immunosorbent assay(ELISA)and compared the autoantibody titers in sera from patients with and without glaucomatous optic neuropathy. Results: Seven positive immunoreactive clones were identified in serum from one male patient aged 59. Their partial DNA sequences revealed that they were derived from 2 different cDNAs. Computer analysis of the deduced amino acid sequences for six of the seven clones revealed that inserted cDNAs coincide with rat neurofilament-H(NF-H). Homology between rat and human cDNA of NF-H was 89%. The prevalence of IgG anti-NF-H autoantibodies in patients(18.2%) was significantly higher than healthy controls (3.8%) (p<0.05). Conclusions. Glaucoma is a disorder characterized by the loss of the retinal ganglion cells and their axons, resulting in progressive visual field loss. Neurofilaments are neuron-specific intermediate filaments serving as major cytoskeletal elements in neurons. NF-H is also known to be a specific marker for ganglion cells. The higher prevalence of anti-NF-H auto-antibodies in glaucomatous patients may indicates that NF-H is a target protein of humoral immune response in glaucoma. This finding suggests that this autoimmune response play a crucial role in development of glaucomatous optic neuropathy.

Keywords: autoimmune disease • cytoskeleton • neuropeptides