Glycan particles

The following protocol describes the oxidation of carbohydrate (glycans) on antibody molecules to form aldehydes and the subsequent coupling to hydrazide particles. 

Several reviews cover dendrimer syntheses and applications [94], but very few describe glycodendrimers as such [16,52,82,95,96]. Dendrimers can basically adopt two shapes spherical, globular-like structmes (58) and monodendritic (59-61) architectures (Scheme 11). The last family is particularly appealing because it can mimic complex multiantennary glycans foimd at the tips of natmal glycoproteins. Moreover, from cumulative observations, spherical dendrimers, particularly large ones (i.e., >16-32-mer) have started to show their intrinsic structmal limitations that is, they suffer from severe steric accessibility. This situation is fmther amplified by the presence of complete bacterial and viral particles wherein the receptors are themselves clustered and congested. Alternatively, they have shown excellent inhibitory properties with soluble or surface-boimd lectins and antibodies. 

Binding of influenza viruses to the human cell surface is mediated by the hemagglutinin (HA) proteins. The attachment initiates the uptake of the virus particle into the host cell. Influenza HAs bind to carbohydrates bearing sialic acids (A-acetylneuraminic acid). The human influenza virus HA proteins preferentially bind to a2-6-linked sialic acids (Fig. 8A) that are found in the upper respiratory tract of humans. In contrast, avian HA proteins preferentially bind to a2-3-hnked sialic acid (Fig. 8B) (61-63). Glycans of this type occur in the respiratory tract and intestine of birds. This way, species specificity of the influenza strains is generated and a barrier exists for avian strains infecting humans, as the sialic acid with an a2-3 linkage is rare on the cell surface of human epithelial cells in the readily accessible upper respiratory tract (61,64). 

A bianteimary glycan with one galactose can have the galactose on either of the two antennae (i.e., linked to the al-3 mannose arm or to the al-6 mannose arm). These isomers are just separated by liquid chromatography on a 3-nm particle-packed colimm (Figure 8.2, IgG, GU 6.6 and 6.7) but can be baseline separated using a 1.7-(im particle-packed colimm (Figure 8.3, IgG, GU 6.8 and 6.9). A similar increase in resolution is... 

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