| Schistosomiasis (bilharzia), is a debilitating and sometimes deadly parasitic helminth infection caused by digenetic Schistosoma species. An estimated 200,000,000 people are chronically infected worldwide, ranking schistosomiasis as one of the most significant parasitic diseases in terms of morbidity and mortality. Schistosomes have a complex life-cycle in which larval, adult worm and egg stages interact with the human host, each playing a role in the immunology, pathology and maintenance of the infection. The paired worms can survive for several years in the bloodstream of the human host. Here they produce hundreds of eggs each day, many of which get trapped in organs of the host where they induce inflammatory lesions that eventually lead to fibrosis and organ failure. Only one drug (praziquantel) effective in killing schistosome worms exists and it does not prevent re-infection. The complex molecular mechanisms of the establishment of the parasite in the host have not been clarified, nor has a potential basis for immunity. The numerous glycans and glycoconjugates expressed by schistosomes have emerged as activators and modulators of the host?s immune system, both at innate and adaptive level. The majority of the antibody responses to schistosomes are directed against glycan antigens. Therefore, schistosome glycosylation constitutes an attractive target area for intervention of schistosome infections. Mass spectrometry(MS)-based analytical studies of schistosome glycans have revealed a relative wealth of structural data. However, these global glycomic surveys have so far only addressed the glycosylation of cercariae, adult worms and eggs. The larval and juvenile life stages of the schistosome that are most important in terms of development and establishment in the host, and which are most likely vulnerable to immune attack, have so far been largely neglected in glycosylation studies. Moreover, structural and functional studies focusing on specifically selected glycan antigens involved in host immunity, rather than on crude mixtures containing many irrelevant glycan elements, are limited. The proposed research project will take up the challenge of the structural analysis of the glycosylation of the early developmental stages of Schistosoma mansoni (from larval to adult worms), in combination with the large scale assessment of the impact of specific glycan elements on the humoral immune response of the infected host. To this end, an innovative MS-based analytical approach combined with the construction and application of a covalent glycan microarray will be employed. The generated data will provide the essential molecular basis for the exploration of glycans as immunogens in in vitro and in vivo models for parasitic infections. The objectives of the project are: - glycomic analysis of 3h-, 24h-, 3d-, 6d-old schistosomula, lung-stage worms, 2w-, 3w-, 4w-, 5w-, 6w-old worms using an MS-based analytical approach - construction of a glycan microarray containing all isolated glycans - selection of glycan antigens and corresponding antibodies specific for the larval and juvenile developmental stages by probing micro arrays with infection sera and monoclonal antibodies (mAbs) - initial exploration of the protective potential of glycans and anti-glycan antibodies in vitro (schistosomula killing) and in vivo (mouse infection model) The proposed research is perfectly embedded in - and supported by - the research group with its unique combination of complex MS-based glycosylation analysis and parasite biochemistry/immunology expertise. The results of this project will provide an essential platform for studies into immunological and biological aspects of schistosomiasis and other infectious diseases which depend on a thorough understanding of the biomolecular background of the host-pathogen interaction. |
