title: Reduced immunogenicity of beta-lactoglobulin by conjugating with chitosan.
abstract: Bovine beta-lactoglobulin (beta-LG) was conjugated with chitosan (CHS) by means of a water-soluble carbodiimide to reduce the immunogenicity of beta-LG. Each beta-LG-CHS conjugate was purified by ion-exchange chromatography and hydrophobic chromatography. The conjugation between beta-LG and CHS was confirmed by SDS-PAGE, the isoelectric point of the conjugate being higher than that of beta-LG. Two types of the beta-LG-CHS conjugate were obtained with molar ratios of beta-LG to CHS of 1:1 (F1) and 1:2 (F2). Structural analyses by fluorescence measurement, ELISA with monoclonal antibodies and retinol-binding activity indicated that the conjugates had almost maintained the native structure of beta-LG. The antigenicity of the beta-LG-CHS conjugates was similar to that of beta-LG in C3H/He mice. Reduction of the immunogenicity of beta-LG was achieved by conjugation with CHS. In particular, F2 showed very low immunogenicity. B cell epitopes of beta-LG and the conjugates recognized in C3H/He mice were determined with 15-mer multi-pin peptide; the linear epitope profiles of the conjugates were found to be similar to those of beta-LG, while the antibody response to each epitope was dramatically reduced. Conjugation of beta-LG with chitosan was effective for reducing the immunogenicity of beta-LG.
authors.affiliation: Institute of Symbiotic Science and Technology, Division of Agriscience and Bioscience, Tokyo University of Agriculture and Technology, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Aoki
authors.forename: Silvia
authors.initials: S
authors.lastname: Iskandar
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Koji
authors.initials: K
authors.lastname: Takahashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Hattori
mesh_terms: D000818:Animals; D002234:Carbodiimides; D002417:Cattle; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents; D004797:Enzyme-Linked Immunosorbent Assay; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D007782:Lactoglobulins / Q000737:chemistry* / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D015394:Molecular Structure; D014801:Vitamin A / Q000378:metabolism
chemical_list: D002234:Carbodiimides; D003432:Cross-Linking Reagents; D018985:Epitopes, B-Lymphocyte; D007782:Lactoglobulins; D014801:Vitamin A; D048271:Chitosan