title: Alpha actinin is specifically recognized by Multiple Sclerosis autoantibodies isolated using an N-glucosylated peptide epitope.
abstract: Sophisticated approaches have recently led to the identification of novel autoantigens associated with Multiple Sclerosis (MuS), e.g. neurofascin, contactin, CNPase, and other T-cell receptor membrane anchored proteins. These putative antigens, although differing from the conventional myelin derivatives, are conceptually based on an animal model of experimental autoimmune encephalomyelitis. In this report we describe the identification of putative antigens based on their recognition by autoantibodies isolated from MuS patient serum. In a previous work from this laboratory we have shown that a peptide probe, named CSF114(Glc), specifically identifies serum autoantibodies in a subset of MuS patients, representing ∼30% of the patient population. The autoantibodies, purified from MuS patients' sera (six), through CSF114(Glc) affinity chromatography, detected three immunoreactive protein bands present in the rat brain. Proteomic analysis of the immunoreactive bands, involving MALDI and MS/MS techniques, revealed the presence of four proteins distinguishable by their mass: alpha fodrin, alpha actinin 1, creatine kinase, and CNPase. The immunoreactive profile of these rat brain proteins was compared with that of commercially available standard proteins by challenging against either CSF114(Glc) purified MuS autoantibodies, or monoclonal antibodies. Further discrimination among the rat brain proteins was provided by the following procedure: whereas monoclonal antibodies recognized all rat brain proteins, isolated MuS specific antibodies recognize only alpha actinin 1 as a putative antigen. In fact, alpha actinin 1 displayed a robust immunoreactive response against all MuS patients' sera examined, whereas the other three bands were not consistently detectable. Thus, alpha actinin 1, a cytoskeleton protein implicated in inflammatory/degenerative autoimmune diseases (lupus nephritis and autoimmune hepatitis) might be regarded as a novel MuS autoantigen, perhaps a prototypic biomarker for the inflammatory/degenerative process typical of the disease.
authors.affiliation: Laboratory of Peptide and Protein Chemistry and Biology, University of Florence, Via della Lastruccia 13, I-50019 Sesto Fiorentino, Italy.
authors.forename: Shashank
authors.initials: S
authors.lastname: Pandey
authors.forename: Ilaria
authors.initials: I
authors.lastname: Dioni
authors.forename: Duccio
authors.initials: D
authors.lastname: Lambardi
authors.forename: Feliciana
authors.initials: F
authors.lastname: Real-Fernandez
authors.forename: Elisa
authors.initials: E
authors.lastname: Peroni
authors.forename: Giulia
authors.initials: G
authors.lastname: Pacini
authors.forename: Francesco
authors.initials: F
authors.lastname: Lolli
authors.forename: Roberta
authors.initials: R
authors.lastname: Seraglia
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Papini
authors.forename: Paolo
authors.initials: P
authors.lastname: Rovero
mesh_terms: D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000097:blood / Q000276:immunology; D000185:Actinin / Q000097:blood / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000097:blood / Q000276:immunology; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D001324:Autoantigens / Q000097:blood / Q000276:immunology*; D001921:Brain / Q000276:immunology / Q000378:metabolism; D002352:Carrier Proteins / Q000097:blood / Q000276:immunology; D052276:Creatine Kinase, BB Form / Q000097:blood / Q000276:immunology; D000939:Epitopes / Q000097:blood / Q000276:immunology; D006031:Glycosylation; D006801:Humans; D008840:Microfilament Proteins / Q000097:blood / Q000276:immunology; D008969:Molecular Sequence Data; D009103:Multiple Sclerosis / Q000097:blood / Q000276:immunology* / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000097:blood / Q000276:immunology*; D010455:Peptides / Q000097:blood / Q000276:immunology*; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry; D013049:Spectrin
chemical_list: D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases; D000185:Actinin; D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D001324:Autoantigens; D002352:Carrier Proteins; D052276:Creatine Kinase, BB Form; D000939:Epitopes; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D010455:Peptides; D013049:Spectrin