Glyco-epitope

Similar results were recently obtained with a human monoclonal antibody, with KDEL sequences fused to the C-termini of both heavy chains, expressed in tobacco [33]. As observed for the invertase-HDEL fusion, about 90% of the N-linked glycans on this antibody were of the high-mannose type, with 6-9 mannose residues, while a fraction contained the immunogenic P(l,2)-xylose glyco-epitope (Fig. 15.6). However, this antibody was not a(l,3)-fucosylated, a glycan modification occurring in the trans Golgi [34]. 

Bardor, M., Faveeuw, C., Fitchettew, A.-C., Gilbert, D., Galas, L Trottein, F., Faye, L., and Lerouge, P. (2003). Immunoreactivity in mammals of two typical plant glyco-epitopes, core a(l, 3)-fucose and core p(l, 2)-xylose. 

Recently, a novel vaccine concept based on nanosized polymer-linked vaccines, has been explored. In particular tumor-associated MUCl glyco-peptides and T-cell epitope peptides were coupled to watersoluble methacrylamide polymers the subsequent attachment of the tetanus toxoid T-cell epitope P2 onto the hydrophilic polymer vaccines, causes their self-assembly to micelle-like nanoobjects. These novel polymer-based glycopeptide vaccines induced significant MHC-II-mediated immune reactions in mice and elicit IgG antibodies, which recognize breast tumor cells. 

A similar problem was encountered during the synthesis of the glycans of glyco-dellin-S [36]. The synthesis of Lewis epitope 26 required bis-a-fucosylation of lac-tosamine moiety 24 (Scheme 6). The tri-O-benzylated fucosyl donor 25 provided the tetrasaccharide 26 with acceptable selectivity but unfortunately as an inseparable mixture. Recourse to a bromide donor under halide ion catalysis (as in the previous example) was not successful because the deactivation was so great it made glyco-sylation of the hindered hydroxyls prohibitively slow. Deactivating the donor species by acetylating the 3- and 4-positions (27) [45], however, increased the a-selectivity to the point that the other anomer was unobservable. 

---