RESUMEN
The oligosaccharide glycosides beta-D-Glcp-(1----6)-beta-D-Glcp-(1----6)-[beta-D-Galp-(1----6)]n-beta-D - Glcp-(1----6)-beta-D-Glcp-1----OMe (n = 1-4) were prepared by a convergent block synthesis. Haloacetyl, tert-butyldiphenylsilyl, and dimethylthexylsilyl groups were used as temporary protective groups for the preparation of the intermediate glycosyl donors and acceptors. The deoxygenated trisaccharide glycosides beta-D-Glcp-(1----6)-beta-D-Galp-(1----6)-4-deoxy-beta-D-xylo-Hexp -1----OMe and beta-D-Glcp-(1----6)-4-deoxy-beta-D-xylo-Hexp-(1----6)-beta-D-Galp -1----OMe were also synthesized. The binding of each glycoside to the monoclonal antigalactan antibody IgA J539 was studied and the results support the previous finding that J539 can bind to internal antigenic epitopes. The data are consistent with the interpretation that subsite C of that antibody binds glucose with a Ka of approximately 6 (cf. 10.9 for galactose).
Asunto(s)
Sitios de Unión de Anticuerpos , Disacáridos/química , Epítopos/química , Metilglicósidos/química , Anticuerpos Monoclonales/química , Conformación de Carbohidratos , Secuencia de Carbohidratos , Disacáridos/inmunología , Metilglicósidos/inmunología , Datos de Secuencia MolecularRESUMEN
The recent advent of synthetic antigens containing the Mycobacterium leprae-specific epitope, 3,6-di-O-methyl-beta-D-glucopyranoside, has allowed the development of simple specific serological tests for leprosy. The incorporation of one such product, 8-carbonyloctyl O-[4-O-(3,6-di-O-methyl-beta-D-glucopyranosyl)-alpha-L- rhamnopyranoside]-BSA, into a simple "spot" test, diffusion-in-gel enzyme-linked immunosorbent assay (ELISA), allowed an over 90% detection rate of untreated lepromatous leprosy, and the results showed good concordance with conventional ELISA based on the native phenolic glycolipid I.
Asunto(s)
Antígenos Bacterianos/inmunología , Glicoproteínas/inmunología , Lepra/diagnóstico , Metilglucósidos/inmunología , Metilglicósidos/inmunología , Mycobacterium leprae/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Glucolípidos/inmunología , Glicoproteínas/síntesis química , Humanos , Inmunodifusión , Pruebas SerológicasRESUMEN
The I- and i-antigen activities of chemically synthesized, linear oligosaccharides of the neolacto series containing one, two or three N-acetyllactosamine (Gal beta 1----4GlcNAc) units have been tested by inhibition of binding of five anti-i and eight anti-I monoclonal antibodies to radioiodinated I- and i-active glycoproteins. The inhibitory activities of the milk oligosaccharides lacto-N-neotetraose (Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc) and lacto-N-tetraose (Gal beta 1----3GlcNAc beta 1----3Gal beta 1----4Glc) have also been determined. The results clearly show that: (a) the determinants that best fit the combining sites of anti-i antibodies are at least hexasaccharides of the neolacto series, (b) linear tetra- and hexasaccharides of the neolacto series can strongly inhibit the binding of anti-I antibodies of group 2 which are known to be primarily directed at the repeating Gal beta 1----4GlcNAc beta 1----3 domains of branched neolacto sequences, (c) the beta- but not the alpha-methyl anomer of the glycoside Gal beta 1----4GlcNAc beta 1-O-Me inhibits the binding of anti-I antibodies of group 1 which recognise the branch point sequence Gal beta 1----4GlcNAc beta 1----6-, (d) the reactivity of the beta-methylglycoside is impaired if the sequence is further elongated as in Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4GlcNAc beta-O-Me, and (e) lacto-N-tetraose has no inhibitory activity with any of the anti-i or anti-I antibodies tested.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Antígenos de Grupos Sanguíneos/inmunología , Sistema del Grupo Sanguíneo I/inmunología , Amino Azúcares/inmunología , Especificidad de Anticuerpos , Sitios de Unión de Anticuerpos , Unión Competitiva , Epítopos/inmunología , Glicoproteínas/inmunología , Humanos , Metilglicósidos/inmunología , Oligosacáridos/inmunología , Relación Estructura-ActividadRESUMEN
Murine monoclonal IgA J539 binds to methyl beta-D-galactopyranoside. With nearly the same affinity, it binds to methyl 6-O-pivaloyl-beta-D-galactopyranoside (4) and to methyl 6-O-beta-D-gentiobiosyl-beta-D-galactopyranoside (7). These observations confirm that the combining area of J539 is of the surface-, and not of the cavity-type.