CHANGES IN GLYCAN DISTRIBUTION WITHIN THE PORCINE INTERHAEMAL BARRIERDURING GESTATION

Changing patterns of glycan distribution are described in porcine plac entae at 15, 19, 26, 33, 58, 69 and 109 days gestation, using a carefu lly selected panel of lectins that allowed partial analysis of sacchar ide classes and sequences. The lectins used were from Galanthus nivali s, Pisum sativum, Phaseolus vulgaris (leukohaemagglutinin), Triticum v ulgaris, Tetragonolobus purpureus, Ulex europaeus-1, Arachis hypogaea, Erythrina cristagalli, Glycine max, Maclura pomifera, Wisteria florib unda, Dolichos biflorus, Maackia amurensis, Sambucus nigra and Limax f lavus. During the course of gestation the trophoblast developed from a smooth to a deeply folded membrane, while enlarging fetal and materna l capillaries grew closer to each other. The feto-maternal interface e xpressed many classes of saccharide, both O- and N-linked, but failed to bind DBA, MAA and SNA. Many granules were present in the maternal e pithelium, and a striking feature was the appearance of staining with DBA and UEA-1 by day 43. This stage of pregnancy was also associated w ith changes in trophoblast glycan expression, with a diminution in sta ining intensity of AHA, MPA and LTA, but an increased intensity with E CA, SBA and WFA. Changes in lectin binding throughout gestation are co rrelated with previous ultrastructural findings and their relevance to the immunological and functional aspects of pregnancy is discussed.