The glycosylation status of murin postnatal thymus: a study by histochemistry and lectin blotting

Abstract

During the intrathymic development, the fate of the thymocytes depends largely on variable expression of CD4/CD8 markers and T cell receptor protein expressions. In addition, changes of cell surface glycosylation status also affect the thymocyte maturation. In this study the glycosylation alterations in thymic tissues from 1, 9, 13 and 16 days old mice were evaluated by histochemical and lectin blotting techniques. With alcian blue (AB) at pH 5.7/periodic acid-Schiff (PAS) stainings, it was shown that thymic microenvironments contained carboxlylated and sulfated glycosaminoglycans (GAGs). Strong positivity to AB at pH 2.5, which specific for sialomucins, was seen in some medullary thymocytes. Similarly, it was shown that with Maackia amurensis agglutinin (MAL) medullary thymocytes, but not cortical ones, contained alpha(2 --> 3) linked sialic acid structures. On the other hand, while reaction with peanut agglutinin (PNA), which specific for core disaccharide galactose beta(1 --> 3) N-acetylgalactosamine, was only seen in cortical thymocytes, reaction with Galanthus nivalis agglutinin (GNA), which specific for terminal mannose residues, was seen in both cortex and medulla. However, Datura stramonium agglutinin (DSA), which recognizes galactose beta(1 --> 4) N-acetylglucosamine, was not only cell-specific, but it was bound some thymic vessels. With lectin blotting studies, five glycoprotein bands of molecular weights approximately 39, approximately 54, 100, approximately 110 and approximately 212 were found which reacted with MAL, PNA and DSA as well as GNA. These results suggest that glycosylation patterns of cell surface glycoconjugates are modified during thymocyte selection processes of postnatal days.

Lectin panel screening for evaluating of murine thymocytes apoptosis stages

“…Лектины арахиса и виноградной улитки преимущественно связывают тимоциты на ранних стадиях созревания. Этот резуль-тат полностью соответствует данным многих исследований, подтверждающих возможность использования лектина арахиса для выделения незрелых кортикальных тимоцитов [39,40]. Данные табл.…”

“…Таким образом, лектины различной углеводной специфичности могут применяться для изучения углеводных детерминант, присутствующих на поверхности клеток тимуса на разных стадиях их созревания, а также для исследования влияния препаратов на структуру гликокаликса клеток тимуса [40][41][42][43]. Отдельное направление исследования представляет исполь зование лектинов как маркеров разных стадий апоптоза [44,45].…”

T cells modulate glycans on CD43 and CD45 during development and activation, signal regulation, and survival

“…C2GnT adds a β1,6‐linked N ‐acetylglucosamine (β1,6‐GlcNAc) to the core 1 structure that can be further extended into a polylactosamine sequence. In the thymus, sialylated core 1 structures are found on double negative immature thymocytes and on mature CD4 or CD8 single positive thymocytes, while asialo‐core 1 and core 2 structures are found on immature double positive thymocytes 16,37–39 . Peripheral naive T cells in general express sialylated core 1 O‐ glycans.…”

“…Thymocytes and T cells can express all three types of N ‐glycans (Table 1). 38,52 High‐mannose N ‐glycan structures can be trimmed by mannosidases to create substrates for glycosyltransferases that create hybrid and complex N ‐glycan structures. Complex N ‐glycans found on T cells can be tri‐ or tetra‐antennary structures created by the action of N ‐acetylglucosaminyltransferase V (GnT‐V).…”