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Author Chacko, B. K. ♦ Appukuttan, P. S.
Source Sree Chitra Tirunal Institute for Medical Sciences & Technology
Content type Text
Publisher Molecular Immunology
File Format PDF
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Life sciences; biology ♦ Physiology & related subjects ♦ Biochemistry ♦ Technology ♦ Medicine & health
Subject Domain (in MeSH) Nutritional and Metabolic Diseases ♦ Diseases ♦ Chemical Phenomena ♦ Immune System Phenomena ♦ Biological Sciences
Subject Keyword Biochemistry
Abstract Dextran-binding antibody was isolated in high yield from plasma of all 40 blood donors screened in a South Indian population. The antibody was purified by a single step affinity chromatography on Sephadex G100 using 1-O-methyl alpha-D-glucoside as eluant. Analysis of protein peaks obtained in size exclusion high pressure liquid chromatography (HPLC) revealed dominance of IgG and suggested the presence of polymeric IgA in this antibody. Methyl and para-nitrophenyl alpha-D-glucosides, in contrast to their beta-anomers, were very efficient inhibitors of binding of this antibody to dextran. Galactose and glucose were equally good inhibitors. Among disaccharide inhibitors sucrose was more efficient than maltose or melibiose. Hemoglobin artificially glycosylated to contain covalently-linked glucose or alpha-anomeric galactose was sugar-specifically recognized by this antibody. Galactose moieties in glycoproteins or polysaccharides were, however, not recognized. The dextran-binding antibody bound sugar-specifically to glycoconjugates from yeast (Saccharomyces cerevisiae) and to lipopolysaccharides from Klebsiella and group A Streptococci, but not to lipopolysaccharides from E. coli. Inhibition studies suggested glucose moiety with unsubstituted C2 and C4 and alpha-anomeric C1 as ideal for recognition by the dextran-binding antibody. Concentration of glucose required for 50% inhibition of binding of the purified antibody to polystyrene-coated dextran in phosphate buffered saline was above the glucose concentrations in normal sera, but well below those reached in diabetic sera. Binding of the antibody from dialysed plasma to immobilized dextran was lowered only marginally in presence of glucose at 4.5 mM (which nears normal serum glucose concentrations), but substantially in presence of the sugar at 20 mM and above which are reached in diabetic sera. If verified in vivo, inhibition of this antibody by high serum glucose may possibly be among reasons for the increased susceptibility of diabetics to infection. (C) 2003 Elsevier Science Ltd. All rights reserved.
Education Level UG and PG
Learning Resource Type Article
Educational Framework Medical Council of India (MCI)
Volume Number 39
Issue Number 15
Page Count 7
Starting Page 933
Ending Page 939