scholarly journals Development and Evaluation of a Cryopreserved Whole-Parasite Vaccine in a Rodent Model of Blood-Stage Malaria

mBio ◽  
2021 ◽  
Author(s):  
Danielle I. Stanisic ◽  
Mei-Fong Ho ◽  
Reshma Nevagi ◽  
Emily Cooper ◽  
Maddison Walton ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Rodent Model ◽  
Blood Stage ◽  
Morbidity And Mortality ◽  
Content Type ◽  
Blood Stage Malaria

Malaria is a mosquito-borne infectious disease that is caused by parasites of the genus, Plasmodium . There are seven different Plasmodium spp. that can cause malaria in humans, with P. falciparum causing the majority of the morbidity and mortality.

scholarly journals The Structure of the Cysteine-Rich Domain of Plasmodium falciparum P113 Identifies the Location of the RH5 Binding Site

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Ivan Campeotto ◽  
Francis Galaway ◽  
Shahid Mehmood ◽  
Lea K. Barfod ◽  
Doris Quinkert ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Binding Site ◽  
Structural Information ◽  
Blood Stage ◽  
Site Directed Mutagenesis ◽  
Effective Vaccine ◽  
Binding Region ◽  
Fab Fragment ◽  
Content Type ◽  
Blood Stage Malaria

ABSTRACT Plasmodium falciparum RH5 is a secreted parasite ligand that is essential for erythrocyte invasion through direct interaction with the host erythrocyte receptor basigin. RH5 forms a tripartite complex with two other secreted parasite proteins, CyRPA and RIPR, and is tethered to the surface of the parasite through membrane-anchored P113. Antibodies against RH5, CyRPA, and RIPR can inhibit parasite invasion, suggesting that vaccines containing these three components have the potential to prevent blood-stage malaria. To further explore the role of the P113-RH5 interaction, we selected monoclonal antibodies against P113 that were either inhibitory or noninhibitory for RH5 binding. Using a Fab fragment as a crystallization chaperone, we determined the crystal structure of the RH5 binding region of P113 and showed that it is composed of two domains with structural similarities to rhamnose-binding lectins. We identified the RH5 binding site on P113 by using a combination of hydrogen-deuterium exchange mass spectrometry and site-directed mutagenesis. We found that a monoclonal antibody to P113 that bound to this interface and inhibited the RH5-P113 interaction did not inhibit parasite blood-stage growth. These findings provide further structural information on the protein interactions of RH5 and will be helpful in guiding the development of blood-stage malaria vaccines that target RH5. IMPORTANCE Malaria is a deadly infectious disease primarily caused by the parasite Plasmodium falciparum. It remains a major global health problem, and there is no highly effective vaccine. A parasite protein called RH5 is centrally involved in the invasion of host red blood cells, making it—and the other parasite proteins it interacts with—promising vaccine targets. We recently identified a protein called P113 that binds RH5, suggesting that it anchors RH5 to the parasite surface. In this paper, we use structural biology to locate and characterize the RH5 binding region on P113. These findings will be important to guide the development of new antimalarial vaccines to ultimately prevent this disease, which affects some of the poorest people on the planet.

scholarly journals Bacterially Expressed Full-Length Recombinant Plasmodium falciparum RH5 Protein Binds Erythrocytes and Elicits Potent Strain-Transcending Parasite-Neutralizing Antibodies

2013 ◽  
Vol 82 (1) ◽  
pp. 152-164 ◽  
Author(s):  
K. Sony Reddy ◽  
Alok K. Pandey ◽  
Hina Singh ◽  
Tajali Sahar ◽  
Amlabu Emmanuel ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Neutralizing Antibodies ◽  
Malaria Vaccine ◽  
Expression System ◽  
Full Length ◽  
Blood Stage ◽  
Parasite Protein ◽  
Content Type ◽  
Erythrocyte Binding ◽  
Blood Stage Malaria

ABSTRACTPlasmodium falciparumreticulocyte binding-like homologous protein 5 (PfRH5) is an essential merozoite ligand that binds with its erythrocyte receptor, basigin. PfRH5 is an attractive malaria vaccine candidate, as it is expressed by a wide number ofP. falciparumstrains, cannot be genetically disrupted, and exhibits limited sequence polymorphisms. Viral vector-induced PfRH5 antibodies potently inhibited erythrocyte invasion. However, it has been a challenge to generate full-length recombinant PfRH5 in a bacterial-cell-based expression system. In this study, we have produced full-length recombinant PfRH5 inEscherichia colithat exhibits specific erythrocyte binding similar to that of the native PfRH5 parasite protein and also, importantly, elicits potent invasion-inhibitory antibodies against a number ofP. falciparumstrains. Antibasigin antibodies blocked the erythrocyte binding of both native and recombinant PfRH5, further confirming that they bind with basigin. We have thus successfully produced full-length PfRH5 as a functionally active erythrocyte binding recombinant protein with a conformational integrity that mimics that of the native parasite protein and elicits potent strain-transcending parasite-neutralizing antibodies.P. falciparumhas the capability to develop immune escape mechanisms, and thus, blood-stage malaria vaccines that target multiple antigens or pathways may prove to be highly efficacious. In this regard, antibody combinations targeting PfRH5 and other key merozoite antigens produced potent additive inhibition against multiple worldwideP. falciparumstrains. PfRH5 was immunogenic when immunized with other antigens, eliciting potent invasion-inhibitory antibody responses with no immune interference. Our results strongly support the development of PfRH5 as a component of a combination blood-stage malaria vaccine.

scholarly journals Identification of a Potent Combination of Key Plasmodium falciparum Merozoite Antigens That Elicit Strain-Transcending Parasite-Neutralizing Antibodies

2012 ◽  
Vol 81 (2) ◽  
pp. 441-451 ◽  
Author(s):  
Alok K. Pandey ◽  
K. Sony Reddy ◽  
Tajali Sahar ◽  
Sonal Gupta ◽  
Hina Singh ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Neutralizing Antibodies ◽  
Malaria Vaccine ◽  
Vaccine Development ◽  
Blood Stage ◽  
Content Type ◽  
Receptor Blocking ◽  
Erythrocyte Invasion ◽  
Invasion Inhibition ◽  
Blood Stage Malaria

ABSTRACTBlood-stage malaria vaccines that target singlePlasmodium falciparumantigens involved in erythrocyte invasion have not induced optimal protection in field trials. Blood-stage malaria vaccine development has faced two major hurdles, antigenic polymorphisms and molecular redundancy, which have led to an inability to demonstrate potent, strain-transcending, invasion-inhibitory antibodies. Vaccines that target multiple invasion-related parasite proteins may inhibit erythrocyte invasion more efficiently. Our approach is to develop a receptor-blocking blood-stage vaccine againstP. falciparumthat targets the erythrocyte binding domains of multiple parasite adhesins, blocking their interaction with their receptors and thus inhibiting erythrocyte invasion. However, with numerous invasion ligands, the challenge is to identify combinations that elicit potent strain-transcending invasion inhibition. We evaluated the invasion-inhibitory activities of 20 different triple combinations of antibodies mixedin vitroagainst a diverse set of six key merozoite ligands, including the novel ligandsP. falciparumapical asparagine-rich protein (PfAARP), EBA-175 (PfF2),P. falciparumreticulocyte binding-like homologous protein 1 (PfRH1), PfRH2, PfRH4, andPlasmodiumthrombospondin apical merozoite protein (PTRAMP), which are localized in different apical organelles and are translocated to the merozoite surface at different time points during invasion. They bind erythrocytes with different specificities and are thus involved in distinct invasion pathways. The antibody combination of EBA-175 (PfF2), PfRH2, and PfAARP produced the most efficacious strain-transcending inhibition of erythrocyte invasion against diverseP. falciparumclones. This potent antigen combination was selected for coimmunization as a mixture that induced balanced antibody responses against each antigen and inhibited erythrocyte invasion efficiently. We have thus demonstrated a novel two-step screening approach to identify a potent antigen combination that elicits strong strain-transcending invasion inhibition, supporting its development as a receptor-blocking malaria vaccine.

scholarly journals Interleukin-3-Deficient Mice Have Increased Resistance to Blood-Stage Malaria

2013 ◽  
Vol 82 (3) ◽  
pp. 1308-1314 ◽  
Author(s):  
Sarah R. Auclair ◽  
Kenneth E. Roth ◽  
Bryan L. Saunders ◽  
Kathryn M. Ogborn ◽  
Abdalla A. Sheikh ◽  
...  
Keyword(s):  
Critical Role ◽  
Blood Stage ◽  
Erythroid Progenitors ◽  
Content Type ◽  
Interleukin 3 ◽  
Blood Neutrophils ◽  
Csf Levels ◽  
Peak Parasitemia ◽  
Ifn Γ ◽  
Blood Stage Malaria

ABSTRACTThe contribution of interleukin-3 (IL-3), a hematopoietic growth factor and immunoregulatory cytokine, to resistance to blood-stage malaria was investigated by infecting IL-3-deficient (knockout [KO]) mice withPlasmodium bergheiNK65. Male IL-3 KO mice, but not female mice, were more resistant to infection than wild-type (WT) mice, as evidenced by lower peak parasitemia and prolonged survival. Both male and female IL-3 KO mice had increased splenomegaly and were more anemic than corresponding WT mice. Anemia was compensated for by an increase in bone marrow and splenic erythropoiesis in IL-3 KO mice, as evidenced by higher levels of erythroid progenitors. Plasma levels of gamma interferon (IFN-γ) and CXCL9 (monokine induced by IFN-γ [MIG]) were found to be significantly reduced in IL-3 KO mice during early stages of infection. In contrast, granulocyte colony-stimulating factor (G-CSF) levels were significantly higher, and the percentage of peripheral blood neutrophils lower, in infected IL-3 KO mice than in WT counterparts. Overall, our results indicate that IL-3 plays a critical role in suppressing protective immunity toP. bergheiNK65 infection and that it is involved in inhibiting the development of splenomegaly, anemia, and erythropoiesis. IL-3 also influences IFN-γ, CXCL9, and G-CSF production in response to infection. The abnormal responses seen in infected IL-3 KO mice may be due to the lack of IL-3 during development, to the lack of IL-3 in the infected mature mice, or to both.

scholarly journals Parasite-Specific CD4+IFN-γ+IL-10+T Cells Distribute within Both Lymphoid and Nonlymphoid Compartments and Are Controlled Systemically by Interleukin-27 and ICOS during Blood-Stage Malaria Infection

2015 ◽  
Vol 84 (1) ◽  
pp. 34-46 ◽  
Author(s):  
Ana Villegas-Mendez ◽  
Tovah N. Shaw ◽  
Colette A. Inkson ◽  
Patrick Strangward ◽  
J. Brian de Souza ◽  
...  
Keyword(s):  
T Cells ◽  
Malaria Infection ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Interleukin 10 ◽  
Plasmodium Yoelii ◽  
Blood Stage ◽  
Content Type ◽  
Ifn Γ ◽  
Blood Stage Malaria

Immune-mediated pathology in interleukin-10 (IL-10)-deficient mice during blood-stage malaria infection typically manifests in nonlymphoid organs, such as the liver and lung. Thus, it is critical to define the cellular sources of IL-10 in these sensitive nonlymphoid compartments during infection. Moreover, it is important to determine if IL-10 production is controlled through conserved or disparate molecular programs in distinct anatomical locations during malaria infection, as this may enable spatiotemporal tuning of the regulatory immune response. In this study, using dual gamma interferon (IFN-γ)–yellow fluorescent protein (YFP) and IL-10–green fluorescent protein (GFP) reporter mice, we show that CD4+YFP+T cells are the major source of IL-10 in both lymphoid and nonlymphoid compartments throughout the course of blood-stagePlasmodium yoeliiinfection. Mature splenic CD4+YFP+GFP+T cells, which preferentially expressed high levels of CCR5, were capable of migrating to and seeding the nonlymphoid tissues, indicating that the systemically distributed host-protective cells have a common developmental history. Despite exhibiting comparable phenotypes, CD4+YFP+GFP+T cells from the liver and lung produced significantly larger quantities of IL-10 than their splenic counterparts, showing that the CD4+YFP+GFP+T cells exert graded functions in distinct tissue locations during infection. Unexpectedly, given the unique environmental conditions within discrete nonlymphoid and lymphoid organs, we show that IL-10 production by CD4+YFP+T cells is controlled systemically during malaria infection through IL-27 receptor signaling that is supported after CD4+T cell priming by ICOS signaling. The results in this study substantially improve our understanding of the systemic IL-10 response to malaria infection, particularly within sensitive nonlymphoid organs.

scholarly journals The Blood Stage Antigen RBP2-P1 of Plasmodium vivax Binds Reticulocytes and Is a Target of Naturally Acquired Immunity

2020 ◽  
Vol 88 (4) ◽  
Author(s):  
Anongruk Chim-Ong ◽  
Thitiporn Surit ◽  
Sittinont Chainarin ◽  
Wanlapa Roobsoong ◽  
Jetsumon Sattabongkot ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Malaria Vaccine ◽  
Vaccine Development ◽  
Binding Protein ◽  
Blood Stage ◽  
Content Type ◽  
Binding Inhibition ◽  
Erythrocyte Binding ◽  
Blood Stage Malaria

ABSTRACT The interactions between Plasmodium parasites and human erythrocytes are prime targets of blood stage malaria vaccine development. The reticulocyte binding protein 2-P1 (RBP2-P1) of Plasmodium vivax, a member of the reticulocyte binding protein family, has recently been shown to be highly antigenic in several settings endemic for malaria. Yet, its functional characteristics and the relevance of its antibody response in human malaria have not been examined. In this study, the potential function of RBP2-P1 as an invasion ligand of P. vivax was evaluated. The protein was found to be expressed in schizonts, be localized at the apical end of the merozoite, and preferentially bind reticulocytes over normocytes. Human antibodies to this protein also exhibit erythrocyte binding inhibition at physiologically relevant concentrations. Furthermore, RBP2-P1 antibodies are associated with lower parasitemia and tend to be higher in asymptomatic carriers than in patients. This study provides evidence supporting a role of RBP2-P1 as an invasion ligand and its consideration as a vaccine target.

scholarly journals Granulocyte-Macrophage Colony-Stimulating Factor-Deficient Mice Have Impaired Resistance to Blood-Stage Malaria

2001 ◽  
Vol 69 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Julie Riopel ◽  
MiFong Tam ◽  
Karkada Mohan ◽  
Michael W. Marino ◽  
Mary M. Stevenson
Keyword(s):  
Blood Stage ◽  
Colony Stimulating Factor ◽  
Necrosis Factor Alpha ◽  
Gm Csf ◽  
Tnf Α ◽  
Macrophage Colony Stimulating Factor ◽  
Ifn Γ ◽  
Macrophage Colony ◽  
Stimulating Factor ◽  
Blood Stage Malaria

ABSTRACT The contribution of granulocyte-macrophage colony-stimulating factor (GM-CSF), a hematopoietic and immunoregulatory cytokine, to resistance to blood-stage malaria was investigated by infecting GM-CSF-deficient (knockout [KO]) mice with Plasmodium chabaudi AS. KO mice were more susceptible to infection than wild-type (WT) mice, as evidenced by higher peak parasitemia, recurrent recrudescent parasitemia, and high mortality. P. chabaudiAS-infected KO mice had impaired splenomegaly and lower leukocytosis but equivalent levels of anemia compared to infected WT mice. Both bone marrow and splenic erythropoiesis were normal in infected KO mice. However, granulocyte-macrophage colony formation was significantly decreased in these tissues of uninfected and infected KO mice, and the numbers of macrophages in the spleen and peritoneal cavity were significantly lower than in infected WT mice. Serum levels of gamma interferon (IFN-γ) were found to be significantly higher in uninfected KO mice, and the level of this cytokine was not increased during infection. In contrast, IFN-γ levels were significantly above normal levels in infected WT mice. During infection, tumor necrosis factor alpha (TNF-α) levels were significantly increased in KO mice and were significantly higher than TNF-α levels in infected WT mice. Our results indicate that GM-CSF contributes to resistance to P. chabaudi AS infection and that it is involved in the development of splenomegaly, leukocytosis, and granulocyte-macrophage hematopoiesis. GM-CSF may also regulate IFN-γ and TNF-α production and activity in response to infection. The abnormal responses seen in infected KO mice may be due to the lack of GM-CSF during development, to the lack of GM-CSF in the infected mature mice, or to both.

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