title: Isolation and structural identification of glycopolymers of Bifidobacterium bifidum BIM B-733D as putative players in pathogenesis of autoimmune thyroid diseases.
abstract: Bifidobacterium bifidum 791 (commercially available as B. bifidum BIM B-733D) cell-surface biopolymers (BPs) interact selectively with human serum thyroid peroxidase (TPO) and thyroglobulin (Tg) autoantibodies (anti TPO and anti Tg, respectively). BPanti-TPO and BPanti-Tg were isolated from the soluble fraction of B. bifidum BIM B-733D by affinity chromatography with anti-TPO or anti-Tg, respectively. Homogeneity of affinity eluates (AEanti-TPO and AEanti-Tg) was tested by size exclusion chromatography. For each AE, the elution profiles generated on the basis of absorbance at 280 nm do not conform to ELISA data for functional activity characteristic of BPs. Moreover, high functional activity was detected in chromatographic fractions that had significantly different molecular weights and no absorbance at 280 nm, which suggests a non-protein (carbohydrate) nature of BPanti-TPO and BPanti-Tg. The semi-preparative size exclusion chromatography of AEanti-TPO and AEanti-Tg with detection by refractometer gave 5,000-7,000 Da fractions containing substances that interact selectively with either anti TPO (BPanti-TPO) or anti-Tg (BPanti-Tg) according to ELISA data. Analysis by two-dimensional NMR spectroscopy including a 1H, 13C-heteronuclear single-quantum coherence experiment indicated that both substances are linear α-1,6-glucans. For the first time, an immunological similarity (molecular mimicry) of glycopolymers of B. bifidum BIM B-733D and human thyroid proteins, TPO and Tg, was shown. On the whole, our data point to a possible role of bifidobacteria in the pathogenesis of autoimmune thyroid diseases (ATD). The main requirements for triggering/acceleration or prevention/abrogation of ATD by bifidobacteria through molecular mimicry mechanism are hypothesised to be (1) genetic predisposition to ATD and (2) intestinal epithelium penetration by α-1,6-glucan.
authors: The Institute of Bioorganic Chemistry, National Academy of Sciences of Belaru, Acad. Kuprevicha 5/2, 220141 Minsk, Republic of Belarus.
authors: E P
authors: EP
authors: Kiseleva
authors: The Institute of Bioorganic Chemistry, National Academy of Sciences of Belaru, Acad. Kuprevicha 5/2, 220141 Minsk, Republic of Belarus.
authors: K I
authors: KI
authors: Mikhailopulo
authors: The Institute of Microbiology, National Academy of Sciences of Belarus, Acad. Kuprevicha 5/2, 220141 Minsk, Republic of Belarus.
authors: G I
authors: GI
authors: Novik
authors: Division of Pure and Applied Biochemistry, Lund University, P.O. Box 124, 22100 Lund, Sweden.
authors: E
authors: E
authors: Szwajcer Dey
authors: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospekt 47, 119991 Moscow, Russia.
authors: E L
authors: EL
authors: Zdorovenko
authors: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospekt 47, 119991 Moscow, Russia.
authors: A S
authors: AS
authors: Shashkov
authors: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospekt 47, 119991 Moscow, Russia.
authors: Y A
authors: YA
authors: Knirel
mesh_terms: D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D001323:Autoantibodies / Q000378:metabolism*; D001327:Autoimmune Diseases / Q000209:etiology* / Q000382:microbiology; D001644:Bifidobacterium / Q000737:chemistry / Q000276:immunology*; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D011485:Protein Binding; D013954:Thyroglobulin / Q000276:immunology; D013959:Thyroid Diseases / Q000209:etiology* / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D001323:Autoantibodies; D011135:Polysaccharides, Bacterial; D013954:Thyroglobulin; D007453:Iodide Peroxidase
keywords: autoantibodies; molecular mimicry; α-1,6-glucan