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The present invention relates to a method to produce proteins reduced in high mannose type glycans in a plant or plant cell by partially inhibiting the expression of the Alg3 gene in said plant or plant cell. Said partial inhibition can be provided for by inserting the Alg3 mutant gene from Arabidopsis as derived from the plant line Salk_040296c or by partially inhibiting the endogenous Alg3 gene by providing the plant or plant cell either with an antisense expression, a sense co-suppressing or with an RNA inhibition genetic construct. Optionally also tissue-specific expression of said inhibiting constructs can yield partial inhibition in a plant.

Undec-10-enyl, undec-10-ynyl and 11-azidoundecyl glycoside analogues corresponding to the oligosaccharides of human gangliosides GM3, GM2 and GM1 were synthesized in high yields using glycosyltransferases from Campylobacter jejuni. Due to poor water solubility of the substrates, the reactions were carried out in methanol–water media, which for the first time were shown to be compatible with the C. jejuni α-(2→3)-sialyltransferase (CST-06) and β-(1→4)-N-acetylgalactosaminyltransferase (CJL-30). Bioequivalence of our synthetic analogues and natural gangliosides was examined by binding to Vibrio cholerae toxin and to the B subunit of Escherichia coli heat-labile enterotoxin. This bioequivalence was confirmed by binding mouse and human monoclonal antibodies to GM1 and acute phase sera containing IgM and IgG antibodies to GM1 from patients with the immune-mediated polyneuropathy Guillain–Barré syndrome. The synthesized compounds were analyzed by 1D and 2D 900 MHz NMR spectroscopy. TOCSY and DQF-COSY experiments in combination with 13C–1H correlation measurements (HSQC, HMBC) were carried out for primary structural characterization, and a complete assignment of all 1H and 13C chemical shifts is presented.

The present invention relates to non-mammalian ß-l,4-galactosyltransferases that can be used in their wild-type or in modified forms. The invention further relates to transformed plants and plant cells expressing non-mammalian ß-l,4-galactosyltransferases and methods to produce glycoproteins with altered and preferably mammalian-type glycosylation. The invention additionally provides nucleic acid molecules and expression vectors of non-mammalian ß-l,4-galactosyltransferases.

In this study, we show that introduction of human N-acetylglucosaminyltransferase (GnT)-III gene into tobacco plants leads to highly efficient synthesis of bisected N-glycans. Enzymatically released N-glycans from leaf glycoproteins of wild-type and transgenic GnT-III plants were profiled by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in native form. After labeling with 2-aminobenzamide, profiling was performed using normal-phase high-performance liquid chromatography with fluorescence detection, and glycans were structurally characterized by MALDI-TOF/TOF-MS and reversephase nano-liquid chromatography-MS/MS. These analyses revealed that most of the complex-type N-glycans in the plants expressing GnT-III were bisected and carried at least two terminal N-acetylglucosamine (GlcNAc) residues in contrast to wild-type plants, where a considerable proportion of N-glycans did not contain GlcNAc residues at the nonreducing end. Moreover, we have shown that the majority of N-glycans of an antibody produced in a plant expressing GnT-III is also bisected. This might improve the efficacy of therapeutic antibodies produced in this type of transgenic plant.

The invention comprises a method to produce a Lewis X epitope on N-linked glycans on glycoproteins in a plant, plant part or plant cells, comprising expression of a nucleotide sequence encoding a galactosyltransferase, which catalyzes the addition of galactose in ßl,4-linkage to N-linked glycans, and expression of a nucleotide sequence encoding a fucosy transferase, which catalyzes the addition of fucose in al,3-linkage to the N-acetylglucosamine of GalBl-4GlcNAc structures on N-linked glycans, and expression of one or more nucleotide sequences encoding one or more glycoproteins, which are able to be provided with an N-linked glycan, in said plant, plant part or plant cell. The fucosyltransferase comprises preferably the catalyticaal active domain of FUT9 from T. nigrovi

Different vaccination methods have been applied to protect fish against the detrimental effects of various pathogens. Several studies have shown the potentials of oral vaccination. In theory oral vaccination is an effortless and stress-free method which can be applied at almost any age. In general, however, the vaccine has to be protected to avoid digestion, which results in high costs for application in aquaculture. In this paper we introduce a cost-effective oral vaccination strategy for viral diseases of fish. The vaccines discussed here include fusion proteins consisting of a gut adhesion molecule and a viral peptide expressed in plants. The adhesion molecule mediates binding to and uptake from the gut, whereas the viral peptide functions as vaccine antigen mediating the induction of a humoral immune response. The first pilot studies using a fusion of the gut adhesion molecule and well-characterised heterologous linear B- and T-cell viral epitopes, produced in potato tubers, showed a promising binding and subsequent uptake in the end gut of carp. The results further indicated that a specific humoral immune response was evoked.