Characteristics of interaction of lectins with carbohydrate determinants of secretory immunoglobulin A (sIgA) isolated from colostrum of parturient women

Secretory immunoglobulin A (sIgA) contains glycoconjugates moieties which can be involved in humoral immunity providing antimicrobial defense. The aim of present work was to characterize carbohydrate moieties of sIgA isolated from human colostrum via their interaction with specific lectins. Preparations of sIgA were obtained from 23 colostrums samples of parturient women by 3-fold precipitation with in ammonium sulphate 50% saturation. In the study a panel of 44 lectins of known carbohydrate specificity was used immobilized onto nitrocellulose membrane. The panel was incu­bated with sIgА preparations and lectin-antibody complexes were detected by protein-A conjugated with horseradish peroxidase. Western-blot analysis was applied to cha­racterize glycosylated polypeptides of sIgA isolated from colostrum of parturient women. sIgA from the colostrum of clinically healthy parturient women contained mainly carbohydrate moieties consisting of N-acetyl-D-glucosamine, sialic acid and D-mannose. Substantial differences in interaction of carbohydrate determinants of slgA isolated from colostrum of individual parturient women with the lectines were found. It is proposed that such characteristics can define sensitivity of mother and child to the action of pathogenic microflora.