Carbohydrate- binding proteins (plant/human lectins and autoantibodies from human serum) as mediators of release of lysozyme, elastase, and myeloperoxidase from human neutrophils

Journal/Book: Res. Exp. Med. 195 (5), 153-162. 1995;

Abstract: Analysis of cell surface glycosylation not only provides informationabout cell properties such as their state of differentiation orhistogenetic lineage. The carbohydrate chains also provide potentiallyfunctional binding sites to endogenous carbohydrate-binding proteins.This interaction can elicit consequent signalling processes. Because ofthe importance of neutrophils in the host defence system, we monitoredthe effect of the binding of such sugar receptors to their cell surfaceon the release of the enzymatic activities of lysozyme, elastase, andmyeloperoxidase. Besides the mannose-binding lectin concanavalin A andthe immunomodulatory alpha/beta-galactoside-binding lectin from Viscumalbum L., three preparations of human sugar receptors -beta-galactoside-binding lectin (M(r) 14 kDa) and two affinity-purifiedpolyclonal IgG fractions from serum with the capacity to recognizealpha- or beta-galactosides, respectively - were used. Two animallectins from chicken liver and intestine that bind beta-galactosides, aswell as the lectin-like human serum amyloid P component, were includedin order to assess the importance of slight differences in ligandrecognition. Cytochalasin B-enhanced enzyme release was invariably seenwith the two plant lectins and the chicken liverbeta-galactoside-binding lectin, but the related intestinal lectin didnot increase enzyme release. The mammalian homologue of these avianlectins triggered lysozyme secretion, and the lactoside-binding IgGfraction enhanced the amount of extracellular elastase activity slightlybut significantly. Thus, the actual lectin, not the nominal specificityof sugar receptors, is crucial for elucidation of responses. Due to thehighly stimulatory activity of the two plant lectins, neutrophils frompatients with non-cancerous diseases and from patients with lung cancerwere monitored for the extent of lectin-mediated enzyme release. Onlythe concanavalin A-mediated reactivity of the neutrophils was associatedwith the type of disease. Author.

Keyword(s): ADULT

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