@article{vonBohlKuehnSimonetal.2015, author = {von Bohl, Andreas and Kuehn, Andrea and Simon, Nina and Nkwouano Ngongang, Vanesa and Spehr, Marc and Baumeister, Stefan and Przyborski, Jude M. and Fischer, Rainer and Pradel, Gabriele}, title = {A WD40-repeat protein unique to malaria parasites associates with adhesion protein complexes and is crucial for blood stage progeny}, series = {Malaria Journal}, volume = {14}, journal = {Malaria Journal}, number = {435}, doi = {10.1186/s12936-015-0967-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139728}, year = {2015}, abstract = {Background During development in human erythrocytes, Plasmodium falciparum parasites display a remarkable number of adhesive proteins on their plasma membrane. In the invasive merozoites, these include members of the PfMSP1 and PfAMA1/RON complexes, which facilitate contact between merozoites and red blood cells. In gametocytes, sexual precursor cells mediating parasite transmission to the mosquito vector, plasma membrane-associated proteins primarily belong to the PfCCp and 6-cys families with roles in fertilization. This study describes a newly identified WD40-repeat protein unique to Plasmodium species that associates with adhesion protein complexes of both merozoites and gametocytes. Methods The WD40-repeat protein-like protein PfWLP1 was identified via co-immunoprecipitation assays followed by mass spectrometry and characterized using biochemical and immunohistochemistry methods. Reverse genetics were employed for functional analysis. Results PfWLP1 is expressed both in schizonts and gametocytes. In mature schizonts, the protein localizes underneath the merozoite micronemes and interacts with PfAMA1, while in gametocytes PfWLP1 primarily accumulates underneath the plasma membrane and associates with PfCCp1 and Pfs230. Reverse genetics failed to disrupt the pfwlp1 gene, while haemagglutinin-tagging was feasible, suggesting a crucial function for PfWLP1 during blood stage replication. Conclusions This is the first report on a plasmodial WD40-repeat protein associating with cell adhesion proteins. Since WD40 domains are known to mediate protein-protein contact by serving as a rigid scaffold for protein interactions, the presented data suggest that PfWLP1 supports the stability of adhesion protein complexes of the plasmodial blood stages.}, language = {en} } @article{BoesSpiegelVoepeletal.2015, author = {Boes, Alexander and Spiegel, Holger and Voepel, Nadja and Edgue, Gueven and Beiss, Veronique and Kapelski, Stephanie and Fendel, Rolf and Scheuermayer, Matthias and Pradel, Gabriele and Bolscher, Judith M. and Behet, Marije C. and Dechering, Koen J. and Hermsen, Cornelus C. and Sauerwein, Robert W. and Schillberg, Stefan and Reimann, Andreas and Fischer, Rainer}, title = {Analysis of a multi-component multi-stage malaria vaccine candidate—tackling the cocktail challenge}, series = {PLoS ONE}, volume = {10}, journal = {PLoS ONE}, number = {7}, doi = {10.1371/journal.pone.0131456}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173092}, pages = {e0131456}, year = {2015}, abstract = {Combining key antigens from the different stages of the P. falciparum life cycle in the context of a multi-stage-specific cocktail offers a promising approach towards the development of a malaria vaccine ideally capable of preventing initial infection, the clinical manifestation as well as the transmission of the disease. To investigate the potential of such an approach we combined proteins and domains (11 in total) from the pre-erythrocytic, blood and sexual stages of P. falciparum into a cocktail of four different components recombinantly produced in plants. After immunization of rabbits we determined the domain-specific antibody titers as well as component-specific antibody concentrations and correlated them with stage specific in vitro efficacy. Using purified rabbit immune IgG we observed strong inhibition in functional in vitro assays addressing the pre-erythrocytic (up to 80\%), blood (up to 90\%) and sexual parasite stages (100\%). Based on the component-specific antibody concentrations we calculated the IC50 values for the pre-erythrocytic stage (17-25 μg/ml), the blood stage (40-60 μg/ml) and the sexual stage (1.75 μg/ml). While the results underline the feasibility of a multi-stage vaccine cocktail, the analysis of component-specific efficacy indicates significant differences in IC50 requirements for stage-specific antibody concentrations providing valuable insights into this complex scenario and will thereby improve future approaches towards malaria vaccine cocktail development regarding the selection of suitable antigens and the ratios of components, to fine tune overall and stage-specific efficacy.}, language = {en} }