Flow cytometric analysis of lectin binding to PNEUMOCYSTIS CARINII surface carbohydrates

Journal/Book: J. Parasitol. 78 (2), 271-280. 1992;

Abstract: Pneumocystis carinii obtained from infected rat lung homogenates wasincubated with fluorescein isothiocyanate-conjugated lectins,counterstained with the nuclear stain, propidium iodide (PI), andanalyzed by dual parameter histograms for lectin-associated green andPI-associated red fluorescence using a fluorescence-activated cellsorter. The presence of glucose/mannose moieties was evidenced by thebinding of all organisms to concanavalin A and Wisteria floribunda. Fromthe lectin group specific for N-acetyl-D-glucosamine, P. carinii reactedstrongly with wheat germ agglutinin and less intensely with Solanumtuberosum. Reaction with lectins specific forN-acetyl-D-galactosamine/galactose was variable, probably reflecting thesecondary binding affinities of the lectins used. Soybean agglutinin,Bauhinia purpurea agglutinin, and Maclura pomifera agglutinin reactedmoderately, whereas Dolichos biflorus agglutinin, and Griffoniasimplicifolia I reacted less avidly. The organisms reacted partiallywith Ulex europaeus agglutinin, a lectin specific for fucose, and didnot react well with Arachis hypogaea, Viscum album agglutinin, andGriffonia simplicifolia I beta 4, lectins specific for galactose. A veryweak fluorescent signal was detected with Limax flavus agglutinin,suggesting little or no sialic acid was present. All lectin-bindingreactions were confirmed for specificity by inhibition with the relevantcarbohydrates. Flow cytometric analysis of lung-derived Pneumocystisorganisms stained with fluorescent surface and nuclear dyes provides arapid method for characterization of large parasite populations. Author.

Keyword(s): ANIMAL

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