Degree of sialylation and fucosylation of plasma and amniotic immunoglobulin G changes progressively during normal pregnancy

Abstract

The degree of sialylation and fucosylation of amniotic IgG was associated with the progression of normal pregnancy.

Lectin-based analysis of fucose and sialic acid expressions on human amniotic IgA during normal pregnancy

“…The fetus mucosal system production of IgA is increased and outweighs the mother’s participation and has a direct impact on the glycosylation pattern of amniotic IgA during the 3rd trimester. The same characteristic quantitative switch was previously observed for amniotic IgG [14] and other amniotic glycoconjugates [42] and glycoproteins, namely α1-acid glycoprotein [12] and fibronectin [43]. …”

“…We have observed that in the post-date pregnancy, there was the increase of the fetal or/and placental origin of highly fucosylated and sialylated amniotic IgA glycoforms compared to those at delivery. The changes observed by us for amniotic IgA in the post-date pregnancy group, apart from MAA-reactive glycotopes, overlap/correspond to those reported for the amniotic IgG [14]. These findings can lead to the hypothesis that for amniotic immunoglobulins a common gestational age-dependent mechanism of glycosylation regulation can exist, probably connected with site-dependent synthesis and/or modulation of glycosylation.…”

“…However, the proinflammatory environment which promotes the contraction of the uterus, expulsion of the baby, and rejection of the placenta [40, 47] seems to have no impact on sialylation and fucosylation of amniotic IgA during delivery. We have previously shown that during the delivery amniotic IgG [14] and fibronectin [43], glycoproteins which do not directly take part in response to inflammation (characteristic for acute phase proteins), also showed almost unaltered expression of fucosyl- and sialyl-glycotopes.…”

“…Glycotope expressions on IgA were determined by lectin-IgA-ELISA, in accordance with the procedure described earlier, slightly modified, [14, 33] using specific biotinylated lectins [34] (Vector Laboratories Inc., Burlingame, USA): Maackia amurensis lectin (MAA) [28] and Sambucus nigra lectin (SNA) [29] with binding preferences to sialic acid linked by anomeric glycosidic α2,3 and α2,6 linkages and Lens culinaris lectin (LCA) [30], Tetragonolobus purpureus lectin (LTA) [31], and Ulex europaeus lectin (UEA) [32] showing binding preferences to fucose linked by anomeric glycosidic linkages α1,6, α1,3, and α1,2, respectively. However, the binding specificity of lectins is not absolute and usually covers a range of ligands with different relative affinities.…”

“…Some glycoproteins of amniotic fluid, such as glycodelin, transferrin [10], human chorionic gonadotropin [11], α1-acid glycoprotein [12], fibronectin [13] and IgG [14], represent different schemes of glycosylation, particulary fucosylation and sialylation, in comparison with the glycoproteins of the maternal serum [4]. Moreover, glycosylation patterns of amniotic glycoproteins are reported to change throughout gestation because of different sites of biosynthesis (maternal, fetal, and placental) at subsequent stages of pregnancy [4, 15, 16].…”