Mannose ligands

Fig. 20. Glycocyclodextrins and dendronized cyclodextrin-bearing mannose ligands.

The tetraantennary oligosaccharide illustrated in Figure 14.2 has been shown to present an umbrellalike structure as one of the major conformational populations.14,15 The distance between terminal sugar residues interacting with receptors may vary from 8 to 30 A. In the case of the phosphorylated high-mannose ligands for the MPR, the distance between phosphates is 15 A.16... 

Compound 5 was built with a relatively long PEG spacer arm of defined length (12 ethylene glycol units) (25). The purpose was to provide an optimal accessibility of the liposomal mannose ligands to their receptors (28). However, the PEG spacer arm length can be changed if needed, e.g., for stealth vesicles. 

Figure 4 The mannose binding protein A (MPB-A) binding site featuring van der Waals contacts with the mannose ligand.

Figure 15 Roy s bivalent mannose ligands directed against ConA. To investigate spacing effects, the ligands are designed with variable length linkers.

Recently, Schmidt and coworkers introduced a novel assay to determine binding affinities and IC50 values by mimicking more closely cell-cell contacts and their inhibition. They synthesized soft colloidal particles (SCPs) functionalized with mannose ligands and incubated these microgels on a... 

In 2008, Pohl et al. [12f] described an innovative technology based on fluorous-based carbohydrate microarrays applied to demonstrate that both diastereomers of glycero-D-mannoheptoses fotmd in bacteria bind to ConA. These results showed that this plant lectin can accept modifications at the C-6 position of its natural mannose ligand. 

Because immature dendritic cells display abundant mannose receptors for endo-cytosis or phagocytosis, mannose can be applied to active targeting of chitosan nanoparticles. For interleukin-12 (lL-12) gene delivery to dendritic cells around the tumor cells, mannose ligand was considered for modification of the chitosan nanoparticles [35]. The study showed that mannosylated chitosan and IL-12 plasmid complexes could inhibit tumor growth, and that biocompatible mannosylated chitosan nanoparticles were effective as a gene carrier for cancer immunotherapy. 

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