Sialyl-1 antigen

T. K.-K. Mong, H.-K. Lee, S. G. Duron, and C.-H. Wong, Reactivity-based one-pot total synthesis of fucose GM1 oligosaccharide A sialylated antigenic epitope of small-cell lung cancer, Proc. Nat. Acad. Sci. USA, 100 (2003) 797-802. 

On the other hand, Kren and Thiem have developed a sequential multienzyme one-pot system with cofactor regeneration in order to prepare rather complicated hetero-oligoglycosides such as the sialylated antigen T-epitope... 

In the second example, the synthesis of an I-active ganglioside analogue98 is covered. The sialyl I antigen is shown in Scheme 14. 

SLE Systemic lupus erythematosus SLe Sialyl Lewis X antigen SLO Streptolysin-O SLPI Secretory leucocyte protease inhibitor... 

In order to obtain the biologically interesting sialyl TN antigen glyco-peptides, 7V-(benzyloxycarbonyl)-C -[methyl(5-acetamido-4s7,8,9-tetra-C -acetyl-3,5-dideoxy-D-g/ycmM -D-gtf/0cfo-2-nonulopyranosyl)-onate-(2 — ... 

Fig. 3—Possible solution conformers of oligosaccharide sequences related to the Le and Leb antigens (Lea,Lex, sialyl Le", sialyl Lex, ALeb, ALey). As described in the text, oligosaccharides in solution sample 3D space in local energy-minima wells, so that the conformations shown are approximate only. The models stand only to show the stereochemical hindrance to movement in these branched oligosaccharides. The molecules are shown without the anomeric hydroxyl group. 

Fig. 4—A comparison of the H-D antigenic component and the receptor for influenza virus hemagglutinin, which are a-NeuGc-(2 — 3)-/ -Gal and a-NeuAc-(2 — 3)-/ -Gal, respectively, on the backbones / -D-Gal-( 1 — 4)-jS-d-G1cNAc-( 1 -> 3)-jS-D-Gal-(l - 4)-d-G1cNAc (sialyl i), yS-D-Gal-(l — 4)-yJ-D-GlcNAc-(l - 6)-D-Gal (sialyl I). The CH3 of the acetamido group of Ar-acetylneuraminic acid, which is a CH2OH group in iV-glycolyl-neuraminic acid, is shown.

Independently and at the same time the incorporation of a sialyl-TN-antigen building block in the synthesis of a fragment from the HIV gpl20 glycoprotein was described.41... 

Scheme 13.12 B chain of human a2HS glycoprotein carrying the sialyl-T-antigen.

Selectins mediate contact by binding to carbohydrate-containing receptors on leucocytes through their N-terminal lectin domain. Sialyl-Lewis X (Neu5Aca2-3-Gaipi-4(Fucal-3)Glc-NAc) and derivatives thereof were shown to bind to the selectins and subsequently inhibit ischaemia-induced leucocyte infiltration in the liver [76-78]. A similar compound prevented antigen-induced late bronchial responses and airway hyper-responsiveness in allergic sheep [79]. 

Scheme 21 Synthesis of the 2,6-Sialyl TN-Antigen Building Block Using a Sialyl Donor without a C3 Participating Group[125l...

Scheme 22 Synthesis of the 2,3-Sialyl T-Antigen Building Block and Glycopeptide Using a Donor with a C3 Participating Group 3181...

Biotinylated sialyl Tn antigen with PAA backbone (Sialyl Tn Neu5Aca2-6GalNAca-PAA-biotin, Glycotech). 

For target selection, adhesion molecules are expressed on the surface of endothelial cells. For this purpose, sialyl Lewis X is used as the guide molecule in the case of expression of P- and E-selectins for TNFa-activated HUVEC (human umbilical vein endothelial cells). Thus, targeting membrane-bound antigens in situ is also possible with this technique. 

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