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Author Paul, Anu ♦ Antony, M. ♦ Mathai, J. ♦ Appukuttan, P. S.
Source Sree Chitra Tirunal Institute for Medical Sciences & Technology
Content type Text
Publisher Immunology Letters
File Format PDF
Language English
Subject Domain (in DDC) Technology ♦ Medicine & health ♦ Diseases
Subject Domain (in MeSH) Hemic and Immune Systems ♦ Anatomy ♦ Immune System Diseases ♦ Diseases ♦ Immune System Phenomena ♦ Biological Sciences
Subject Keyword Immunology
Abstract Dextran-binding immunoglobulin (Dig) and anti-beta-glucan antibody (ABG) are naturally occurring human serum antibodies specific to alpha- and beta-glucoside epitopes respectively of polysaccharide antigens and heavily enriched in IgA. ABG and Dig are shown here to have much more of their IgA in polymeric form than does serum IgA in general. Cell wall beta-glucans and glycoproteins of the widely consumed yeast (Saccharomyces cerevisiae) offered several hundred fold better ligands for ABG than did small beta-glucosides. Candida albicans cell wall antigen (CCA), a commonly encountered polysaccharide-rich fungal antigen was recognized by normal human serum anti-carbohydrate antibodies to precipitate maximally at a definite stoichiometry typical of immune complexes (IC). IC formed in serum in vitro on addition of CCA contained a significantly higher percentage of IgA than did either naturally occurring IC or serum. Polymeric IgA was far better ligand than monomeric IgA for both anti-IgA antibody and the most widely expressed human tissue lectin galectin-1 which recognizes O-linked oligosaccharides characteristic of IgA, in contrast to N-linked oligosaccharides present in all immunoglobulins. Moreover, desialylation by neuraminidase, an enzyme released into circulation during many microbial infections and diabetes, increased lectin-binding activity of polymeric IgA much more than that of monomeric IgA. Human galectin-1 immobilized in active form in vitro sugar-specifically captured IgA and IgA-containing IC formed by CCA in serum but not IgG. Results suggest that while high IgA content especially in polymeric form may render polysaccharide IC more susceptible to tissue uptake, desialylation of IgA in IC could enhance the process. (C) 2010 Elsevier B.V. All rights reserved.
Education Level UG and PG
Learning Resource Type Article
Educational Framework Medical Council of India (MCI)
Volume Number 136
Issue Number 1
Page Count 6
Starting Page 55
Ending Page 60