title: Identification of the epitope for anti-cystatin C antibody.
abstract: Human cystatin C (hCC), like many other amyloidogenic proteins, has been shown to form dimers by exchange of subdomains of the monomeric protein. Considering the model of hCC fibrillogenesis by propagated domain swapping, it seems possible that inhibition of this process should also suppress the entire process of dimerization and fibrillogenesis which leads to specific amyloidosis (hereditary cystatin C amyloid angiopathy (HCCAA)). It was reported that exogenous agents like monoclonal antibody against cystatin C are able to suppress formation of cystatin C dimers. In the effort to find a way of controlling the cystatin fibrillization process, the interactions between monoclonal antibody Cyst-13 and cystatin C were studied in detail. The present work describes the determination of the epitope of hCC to a monoclonal antibody raised against cystatin C, Cyst-13, by MALDI mass spectrometry, using proteolytic excision of the immune complex. The shortest epitope sequence was determined as hCC(107-114). Affinity studies of synthetic peptides revealed that the octapeptide with epitope sequence does not have binding ability to Cyst-13, whereas its longer counterpart, hCC(105-114), binds the studied antibody. The secondary structure of the peptides with epitope sequence was studied using circular dichroism and NMR spectroscopy.
authors.affiliation: Department of Medicinal Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Sladewska
authors.forename: Aneta
authors.initials: A
authors.lastname: Szymańska
authors.forename: Marlena
authors.initials: M
authors.lastname: Kordalska
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Lewandowska
authors.forename: Aleksandra S
authors.initials: AS
authors.lastname: Kołodziejczyk
authors.forename: Gabriela
authors.initials: G
authors.lastname: Paraschiv
authors.forename: Michael
authors.initials: M
authors.lastname: Przybylski
authors.forename: Paulina
authors.initials: P
authors.lastname: Czaplewska
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D002942:Circular Dichroism; D055316:Cystatin C / Q000276:immunology*; D004586:Electrophoresis; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry
chemical_list: D000911:Antibodies, Monoclonal; D055316:Cystatin C; D000939:Epitopes