Caglayan-Sozmen S, Santoro A, Cipriani F, Mastrorilli C, Ricci G, et al.
Medicina (Kaunas, Lithuania) •
Childhood food allergies are a growing public health problem. Once the offending food allergens have been identified, a strict elimination diet is necessary in treatment or prevention of most of the allergic reactions. Accidental food ingestion can lead to severe anaphylaxis. Food- derived substances can be used in medications at various stages of the manufacturing process. In this review, the possible roles of medications which may contain egg, red meat, gelatin, and fish allergens on allergic reactions in children with food allergy were evaluated.
Cavallone D, Malagolini N, Monti A, Wu XR, Serafini-Cessi F
The Journal of biological chemistry •
Tamm-Horsfall glycoprotein (THP), the most abundant protein in mammalian urine, has been implicated in defending the urinary tract against infections by type 1-fimbriated Escherichia coli. Recent experimental evidence indicates that the defensive capability of THP relies on its single high mannose chain, which binds to E. coli FimH lectin and competes with mannosylated uroplakin receptors on the bladder surface. Here we describe several major differences, on both structural and functional levels, between human THP (hTHP) and pig THP (pTHP). pTHP contains a much higher proportion (47%) of Man5GlcNAc2 than does hTHP (8%). FimH-expressing E. coli adhere to monomeric pTHP at an approximately 3-fold higher level than to monomeric hTHP. This suggests that the shorter high mannose chain (Man5GlcNAc2) is a much better binder for FimH than the longer chains (Man6-7GlcNAc2) and that pTHP is a more potent urinary defense factor than hTHP. In addition, unlike hTHP whose polyantennary glycans are exclusively capped by sialic acid and sulfate groups, those of pTHP are also terminated by Galalpha1,3Gal epitope. This is consistent with the fact that the outer medulla of pig kidney expresses the alpha1,3-galactosyltransferase, which is completely absent in human kidney. Finally, pTHP is more resistant to leukocyte elastase hydrolysis than hTHP, thus explaining why pTHP is much less prone to urinary degradation than hTHP. These results demonstrate for the first time that the species variations of the glycomoiety of THP can lead to the differential binding of THP to type 1-fimbriated E. coli and that the differences in high mannose processing may reflect species-specific adaptation of urinary defenses against E. coli infections.
Malagolini N, Cavallone D, Wu XR, Serafini-Cessi F
Biochimica et biophysica acta •
Uroplakin III (UPIII) is one of the major transmembrane glycoproteins exposed at the luminal face of mammalian bladder. We investigated the terminal glycosylation of bovine UPIII in order to ascertain whether it contains the alpha 2,3-sialylated sequence thus potentially serving as a receptor for uropathogenic Escherichia coli expressing type S adhesins. We report the occurrence of sialic acid in alpha 2,3- and alpha 2,6-linkage to galactose in bovine UPIII glycans as evidenced by the sensitivity of UPIII to both Vibrio cholera and Newcastle disease virus neuraminidase and by the colocalization of UPIII antigen and material detected by lectins of Sambucus nigra and Maackia amurensis on the luminal face of the bladder. We also present evidence that UPIII glycans are capped by Gal-alpha 1,3-Gal epitope. Consistently, alpha 2,3- and alpha 2, 6-sialyltransferase, as well as alpha 1,3-galactosyltransferase were found to be present in the cells detached from the luminal side of bovine bladder, which are responsible for the UPIII biosynthesis. The putative role of UPIII sialylated glycans in enhancing the uropathogenicity of E. coli expressing type S adhesins is discussed.
Smilovich D, Malagolini N, Fagioli C, de Lalla C, Sitia R, et al.
Glycobiology •
IgM are glycoproteins secreted by plasma cells as (mu2L2)5+J or (mu2L2)6 polymers. In most species, mu- and J-chains bear five and one N -glycans, respectively. Here we compare the terminal glycosylation patterns of 4-hydroxy-3-nitrophenylacetyl (NP)-specific IgM secreted by transfectants of the J558L mouse myeloma deficient in the alpha2,6 sialyltransferase [alpha2,6ST(N)] or by a hybridoma expressing this enzyme (B1.8 cells). The absence of alpha2,6-sialylation results in an increased addition of alpha1, 3-galactosyl residues to mu- and J-chain N-glycans. Since alpha1, 3-galactosyltransferase (alpha1,3Gal-T) is similarly expressed in the two cell lines, these results indicate that a competition reaction occurs in vivo between alpha2,6ST(N) and alpha1,3Gal-T. In the alpha2,6ST(N) deficient transfectants, mu-chains lacking the C-subterminal Cys575 residue, which are secreted mainly in the form of mu2L2 monomers, are more efficiently capped by alpha1, 3-galactosyl residues, confirming that polymerization significantly reduces the accessibility of mu-chain glycans to the Golgi processing enzymes involved in the biogenesis of antennary sugars. Functional assays indicate that IgM sialylation affects antigen-binding and complement-dependent hemolysis of haptenated red blood cells.
