Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated the adhesive capacity of neutrophils after spontaneous apoptosis, which occurs during in vitro culture. Apoptotic neutrophils show reduced adhesion to E selectin and the CD18 integrin ligand fibrinogen. Neutrophil apoptosis is associated with changes in the levels of surface expression of key receptors that mediate neutrophil adhesion events. Notably, apoptotic neutrophils show reduced expression of L-selectin/selectin ligand. In contrast, CD11b/CD18 and CD11c/CD18 integrins are expressed at increased levels. The reduced capacity for adhesion of apoptotic neutrophils may be achieved by very different mechanisms. Regulation of the levels of surface expression of receptors/ligand may control selectin-mediated adhesion, possibly as a result of protease/sialidase activity. In contrast, modulation of integrin-mediated adhesion may involve functional uncoupling of receptors present on the surface of the apoptotic cell without alteration in levels of surface expression. The altered adhesive potential of the apoptotic neutrophil may serve to limit release of its histotoxic contents and reduce inappropriate tissue injury.
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PMID:Regulation of cell adhesion molecule expression and function associated with neutrophil apoptosis. 753 22

As only a few cell surface markers for dendritic cells (DC) have been identified to date, this study examined the expression of ligands for lectin on different human DC populations. The ability of Concanavalin A (Con A), Wheat Germ Agglutinin (WGA), peanut agglutinin (PNA), and Helix pomatia (HPA) to bind to cell lines and PBMC and DC populations was analyzed by flow cytometry and specificity of binding confirmed using inhibitory and noninhibitory sugars. The cell lines showed non-lineage-restricted binding with Con A and WGA, independent of sialidase treatment. HPA and PNA bound to a restricted number of lines, but showed broad reactivity after sialidase treatment. The peripheral blood mononuclear cells (PBMC) and directly isolated blood DC, activated CD83(+) blood DC, epidermal Langerhans cells (LC), and monocyte-derived DC (Mo-DC) showed strong binding of Con A and WGA, both before and after sialidase treatment. No HPA binding ligands were detected on PBMC populations, including directly isolated blood DC. Following sialidase treatment CD3(+), CD16(+), and a subset of CD19(+) lymphocytes bound HPA. The lectin PNA bound weakly to CD14(+) monocytes and a subpopulation of circulating DC that were HLA-DR(hi)CDw123 Dr(hi)CDw123(dim)/(neg)CD11c(+). The HLA-DR(mod)CDw123(hi)CD11c(neg) subpopulation did not bind PNA. Without sialidase treatment LC expressed both HPA and PNA ligands, but these were either absent on activated CD83(+) blood DC or weakly expressed on Mo-DC. Following sialidase treatment PBMC populations, activated CD83(+) blood DC, and Mo-DC became PNA positive. Thus human DC express several lectin ligands and PNA binding identifies a subset of blood DC. That may reflect discrete changes associated with stages of DC development or functional maturation.
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PMID:Lectin ligands on human dendritic cells and identification of a peanut agglutinin positive subset in blood. 1071 81