Reduced immunogenicity of beta-lactoglobulin by conjugating with chitosan

• Published in: Bioscience, biotechnology, and biochemistry biotechnology, and biochemistry, 2006-10, Vol.70 (10), p.2349-2356
• Main Authors: Aoki, T.(Tokyo Univ. of Agriculture and Technology, Fuchu (Japan)), Iskandar, S, Yoshida, T, Takahashi, K, Hattori, M
• Format: Article
• Language: English
• Subjects: ALERGENOS; ALLERGENE; ALLERGENS; Animals; Biological and medical sciences; BOVINA; BOVINAE; Carbodiimides; Cattle; CHITOSAN; Chitosan - chemistry; CHITOSANE; Cross-Linking Reagents; Enzyme-Linked Immunosorbent Assay; Epitopes, B-Lymphocyte - immunology; functional improvement; Fundamental and applied biological sciences. Psychology; IMMUNE RESPONSE; LACTOGLOBULINAS; LACTOGLOBULINE; LACTOGLOBULINS; Lactoglobulins - chemistry; Lactoglobulins - immunology; Lactoglobulins - metabolism; Mice; Mice, Inbred C3H; Molecular Structure; protein conjugation; QUITOSANO; reduced immunogenicity; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; Vitamin A - metabolism; β-lactoglobulin
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.50398

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.