Latest SCI publications
Research project (§ 26 & § 27)
Duration : 2017-07-01 - 2021-06-30
Haemonchus contortus is one of the major helminthic parasites, which infects sheep and goats resulting in economic loss of the ruminant industry worldwide. In comparison to the usage of anthelmintic reagents which can cause resistance among parasitic nematodes, vaccination represents a sustainable and effective approach. Vaccination with a mixture of native Haemonchus gut glycoproteins (namely H11 antigens) has shown effective protection in lambs. However, attempts to produce these antigens recombinantly in various expression hosts and use them as vaccines resulted in either low or no protection in animal trials. As the native H11 antigens are known to carry additional modifications with sugars on the surface of proteins (termed “glycosylation”), which plays an important role in the biological function of antigens, investigation on how to mimic these natural sugar modifications on the recombinant H11 became necessary and will facilitate the production of effective antigens. The sugar structures on the native H11 antigens possess a special “core” modified with up to three fucose residues, which are enzymatically synthesised by three fucosyltransferases. A commercial insect cell line (Hi5) is a suitable host for glycoengineering using recombinant baculovirus to introduce genes encoding Caenorhabditis elegans glyco-enzymes, which can be used to effectively remodel the sugars on the selected helminth reporter. Full length nematode glyco-enzyme encoding sequences are sufficient for Golgi targeting and realising glycoengineering in insect cells. The biological role of C. elegans glyco-enzymes will be investigated by studying the N-glycomes of relevant mutants using HPLC and mass spectrometers as major tools. Recombinant baculoviruses carrying genes encoding two C. elegans glyco-enzymes and DNA sequences encoding Haemonchus H11 (expression targets) will be prepared using molecular biology approaches to produce H11 antigens in Hi5 insect cells. In addition to the protein sequences and peptidase activities, the biochemical properties of glyco-engineered H11 antigens will be evaluated focusing on the sugar modifications and other potential protein modifications. This is probably the first attempt to express helminth antigens modified with authentic sugars in insect cells. The glyco-engineered recombinant H11 antigens are expected to better mimic the native H11 antigens; therefore they may serve as a vaccine candidate in animal trials to protect ruminants from Haemonchus infection.
Synthetic bacterial analogs of mammalian oligomannose for eliciting neutralizing antibodies to the high-mannose patch on HIV env
Research project (§ 26 & § 27)
Duration : 2017-11-01 - 2021-10-31
PROJECT SUMMARY A number of Abs targeting oligomannose-type glycans on the HIV envelope spike (Env) have been described in recent years that exhibit broad neutralizing activity (bnAbs). However, eliciting such nAbs by immunization has not been very successful so far. A principal problem may be the host origin of the glycans, with immune tolerance mechanisms limiting the frequency or development of B cells capable of producing Abs with specificity for mammalian oligomannose. For example, Abs elicited by glycoconjugate immunogens presenting oligomannosides are generally unable to bind oligomannose on Env and even when Env-binding Abs have been obtained, such as with recombinant yeast, they appear to bind insufficiently avid to the virus and fail to exert meaningful neutralizing activity. Here, we propose to utilize bacterially derived oligosaccharide analogs of oligomannose to overcome these challenges. We focus in this application on a fairly conserved patch of high-mannose glycans at and surrounding Asn301 and Asn332 on HIV gp120. Prototypic for Abs targeting these oligomannose-type glycans is the PGT128 family of nAbs, which are potent and broadly active, suggesting that a vaccine component able to elicit similar nAbs could offer protection at even modest serum Ab concentrations. We not long ago discovered a bacterial oligosaccharide that closely resembles the D1 arm of mammalian oligomannose and subsequently made synthetic derivatives of it with a D3 arm-like extension. One of these derivatives, in the form of a neoglycoconjugate, is bound avidly by PGT128 family members and, notably, their predicted germline predecessor. More importantly, data from a pilot immunization with the lead conjugate in transgenic animals harboring an unarranged human Ab repertoire show elicitation of oligomannose-specific Abs with HIV cross-neutralizing activity. Here, we propose to expand on these encouraging preliminary studies. Specifically, we wish to elaborate on our conjugate design to heighten Ab responses and continue to utilize transgenic animals to identify an optimal adjuvant+conjugate combination. We also will dissect antibody responses at the serum and repertoire levels to determine similarities between the elicited responses and existing nAbs. Finally, we propose to test our strategy also in macaques to assess the extent to which it may work in outbred systems. In sum, this project will investigate whether glycan mimicry can serve to readily trigger the development of cross-reactive Abs to the highly vulnerable oligomannose patch on HIV Env. If so, this work could inform strategies for targeting other glyco-epitopes on HIV-1.
Research project (§ 26 & § 27)
Duration : 2017-10-01 - 2020-09-30
Eels are an endangered species of which the migration behaviour is only little understood. In this research project, analysis of eel otoliths and eel soft tissues by means of (LA)-ICP-SFMS and (LA)-MC ICP-MS for elemental (Li, Ba, Mg, B, Fe, Zn, Sr, Ca, Mn, Zr, Pb, U, S) and 87Sr/86Sr isotope analysis. Eel of different provenance will be provided. A special focus is set on glass-eel, representing the juvenile status of the fish. Since the samples are extremely challenging, existing analytical protocols will be further developed and optimized for the respective research question. The to be developed database will be compared with water data in order to reconstruct migration and provenance of the investigated fish samples.