Chemoenzymatic synthesis and immunological studies of Xylosylated N-glycans

307 p.Glycosylation is one of the most common post-translational modifications in eukaryotic cells. It changes during cell development and differentiation and it is tissue and more importantly, species specific. While core ¿-1,6 fucose and/or terminal sialyl residues are typical mammalian features, most of the plant, insects and parasite derived N-glycans contain core ¿-1,3-fucose, ß-1,2-xylose and other terminal motifs. In mammals, some of these glycan elements are believed to be at least partially involved in the stimulation or regulation of immune responses in parasite infected individuals and in the pathophysiology of food allergens. In this Thesis, the chemoenzymatic synthesis of 39 core xylosylated N-glycans is described. Using glycan microarray-assisted studies, the carbohydrate interaction with biologically relevant glycan binding proteins such as plant lectins and animal C-type lectin receptors has been evaluated. Additionally, glycan microarrays were employed for the screening of anti-carbohydrate antibodies raised against S. mansoni parasites. The immune response induced in patients from endemic areas has been compared and the potential biological role of different glycan families is discussed.CIC BioGun

Chemoenzymatic synthesis and immunological studies of Xylosylated N-glycans

307 p.Glycosylation is one of the most common post-translational modifications in eukaryotic cells. It changes during cell development and differentiation and it is tissue and more importantly, species specific. While core ¿-1,6 fucose and/or terminal sialyl residues are typical mammalian features, most of the plant, insects and parasite derived N-glycans contain core ¿-1,3-fucose, ß-1,2-xylose and other terminal motifs. In mammals, some of these glycan elements are believed to be at least partially involved in the stimulation or regulation of immune responses in parasite infected individuals and in the pathophysiology of food allergens. In this Thesis, the chemoenzymatic synthesis of 39 core xylosylated N-glycans is described. Using glycan microarray-assisted studies, the carbohydrate interaction with biologically relevant glycan binding proteins such as plant lectins and animal C-type lectin receptors has been evaluated. Additionally, glycan microarrays were employed for the screening of anti-carbohydrate antibodies raised against S. mansoni parasites. The immune response induced in patients from endemic areas has been compared and the potential biological role of different glycan families is discussed.CIC BioGun

Bank Islam serah zakat perniagaan kepada UMP

KUANTAN 7 Ogos - Bank Islam Malaysia Berhad (BIMB) menyerahkan zakat perniagaan berjumlah RM30,000 kepada Universiti Malaysia Pahang (UMP) untuk disalurkan kepada mahasiswa kurang berkemampuan

Cross-reactivity of glycan-reactive HIV-1 broadly neutralizing antibodies with parasite glycans

The HIV-1 Envelope glycoprotein (Env) is the sole target for broadly neutralizing antibodies (bnAbs). Env is heavily glycosylated with host-derived N-glycans, and many bnAbs bind to, or are dependent upon, Env glycans for neutralization. Although glycan-binding bnAbs are frequently detected in HIV-infected individuals, attempts to elicit them have been unsuccessful because of the poor immunogenicity of Env N-glycans. Here, we report cross-reactivity of glycan-binding bnAbs with self- and non-self N-glycans and glycoprotein antigens from different life-stages of Schistosoma mansoni. Using the IAVI Protocol C HIV infection cohort, we examine the relationship between S. mansoni seropositivity and development of bnAbs targeting glycan-dependent epitopes. We show that the unmutated common ancestor of the N332/V3-specific bnAb lineage PCDN76, isolated from an HIV-infected donor with S. mansoni seropositivity, binds to S. mansoni cercariae while lacking reactivity to gp120. Overall, these results present a strategy for elicitation of glycan-reactive bnAbs which could be exploited in HIV-1 vaccine development.This project has received funding from the European Union’s Horizon 2020 Research and Innovation program under grant agreement 681137 (to K.J.D. and I.H.), the Medical Research Council (MRC) (to K.J.D. [MR/K024426/1]), The Rosetrees Trust (to K.J.D. [M686]) and Fondation Dormeur, Vaduz (to K.J.D). This research was funded or supported by the National Institute for Health Research Biomedical Research Centre based at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London and/or the NIHR Clinical Research Facility. The views expressed are those of the authors and not necessarily those of the National Health Service (NHS), the National Institute for Health Research (NIHR), or the Department of Health. N.R. acknowledges funding from Ministry of Science and Education grants CTQ2017-90039-R, RTC-2017-6126-1, and CTQ2011-27874 (fellowship to K.B.) and the Maria de Maeztu Units of Excellence Program from the Spanish State Research Agency (grant MDM-2017-0720). F.A. was funded by the Wellcome Trust (104958/Z/14/Z). J.A. was supported by the Spanish Ministry of Science, Innovation and Universities through the grant PID2019-109395GB-I00. J.A. and S.M. acknowledge support of BBSRC (grant BB/P010660/1). T.H. and S.W. were funded by Biotechnology and Biological Sciences Research Council (BBSRC) Norwich Research Park Doctoral Training Grant BB/M011216/1. IAVI’s work is made possible by generous support from many donors, including the Bill & Melinda Gates Foundation, the Ministry of Foreign Affairs of Denmark, Irish Aid, the Ministry of Finance of Japan in partnership with The World Bank, the Ministry of Foreign Affairs of the Netherlands, the Norwegian Agency for Development Cooperation, the United Kingdom Department for International Development (DFID), and the United States Agency for International Development. The full list of IAVI donors is available at www.iavi.org. Brendan McAtarsney and Jonathan Hare from the IAVI Human Immunology Lab (HIL) for coordinating the samples transfers and shipments. Monica Agromayor and the KCL Nikon Centre for assistance and advice on confocal microscopy. NMRI strain Schistosoma mansoni-infected Biomphalaria glabrata snails were provided by the NIAID Schistosomiasis Resource Center, Rockville, USA.Peer reviewe

Cross-reactivity of glycan-reactive HIV-1 broadly neutralizing antibodies with parasite glycans

The HIV-1 Envelope glycoprotein (Env) is the sole target for broadly neutralizing antibodies (bnAbs). Env is heavily glycosylated with host-derived N-glycans, and many bnAbs bind to, or are dependent upon, Env glycans for neutralization. Although glycan-binding bnAbs are frequently detected in HIV-infected individuals, attempts to elicit them have been unsuccessful because of the poor immunogenicity of Env N-glycans. Here, we report cross-reactivity of glycan-binding bnAbs with self- and non-self N-glycans and glycoprotein antigens from different life-stages of Schistosoma mansoni. Using the IAVI Protocol C HIV infection cohort, we examine the relationship between S. mansoni seropositivity and development of bnAbs targeting glycan-dependent epitopes. We show that the unmutated common ancestor of the N332/V3-specific bnAb lineage PCDN76, isolated from an HIV-infected donor with S. mansoni seropositivity, binds to S. mansoni cercariae while lacking reactivity to gp120. Overall, these results present a strategy for elicitation of glycan-reactive bnAbs which could be exploited in HIV-1 vaccine development

Development of bio-orthogonal fluorescent tags for carbohydrate analysis and functional assays

Heterogeneous populations of structurally complex carbohydrates mediate many biological important processes, such as cell-cell adhesion, signal transduction and pathogen recognition events. However, due to the non-template driven nature of glycan biosynthesis and very often challenging synthetic routs, the accessibility of these information rich structures is limited and, consequently, their study presents significant challenges limiting progress in glycomics. Here, we will present our recent efforts to develop novel fluorescent tags bearing bio-orthogonal modifications enabling chromatographic separation of glycans obtained from natural sources and their downstream uses in functional assays, like glycan microarrays. These labels will be based upon 2-anthranilic acid and 2-aminobenzamide employed in industrial glycan analysis. Our tags will carry additional ‘clickable’ alkyne, norbornene or tetrazine modifications enabling the conjugation with appropriately functionalised ligation partners (e.g. lipids) via copper catalysed alkyne-azide cycloaddition or via catalyst-free inverse electron demand Diels-Alder reactions. Finally, we will show labelling of commercially available carbohydrates and a mixture of linear glucose oligomers prepared by the acidic hydrolysis of dextran with the novel labels and test their performance, effectiveness, and stability compared to commercial tags. The selected labels will also be used to tag glycans mixtures of N-linked carbohydrates cleaved enzymatically from the model glycoproteins. We believe that developed fluorescent bio-orthogonal tags will provide exciting methodology for utilisation of natural glycan resources, generation of complex neo-glycoconjugates and functional assays, making carbohydrates more accessible to the wider community

Chemoenzymatic synthesis and immunological studies of Xylosylated N-glycans

307 p.Glycosylation is one of the most common post-translational modifications in eukaryotic cells. It changes during cell development and differentiation and it is tissue and more importantly, species specific. While core ¿-1,6 fucose and/or terminal sialyl residues are typical mammalian features, most of the plant, insects and parasite derived N-glycans contain core ¿-1,3-fucose, ß-1,2-xylose and other terminal motifs. In mammals, some of these glycan elements are believed to be at least partially involved in the stimulation or regulation of immune responses in parasite infected individuals and in the pathophysiology of food allergens. In this Thesis, the chemoenzymatic synthesis of 39 core xylosylated N-glycans is described. Using glycan microarray-assisted studies, the carbohydrate interaction with biologically relevant glycan binding proteins such as plant lectins and animal C-type lectin receptors has been evaluated. Additionally, glycan microarrays were employed for the screening of anti-carbohydrate antibodies raised against S. mansoni parasites. The immune response induced in patients from endemic areas has been compared and the potential biological role of different glycan families is discussed.CIC BioGun