scholarly journals Identification of Plasmodium falciparum proteoforms from liver stage models

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Benjamin Winer ◽  
Kimberly A. Edgel ◽  
Xiaoyan Zou ◽  
Julie Sellau ◽  
Sri Hadiwidjojo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Plasmodium Falciparum ◽  
Vaccine Development ◽  
Strongly Correlated ◽  
T Cell Epitopes ◽  
Liver Stage ◽  
Stage Models ◽  
Erythrocyte Antigen

Abstract Background Immunization with attenuated malaria sporozoites protects humans from experimental malaria challenge by mosquito bite. Protection in humans is strongly correlated with the production of T cells targeting a heterogeneous population of pre-erythrocyte antigen proteoforms, including liver stage antigens. Currently, few T cell epitopes derived from Plasmodium falciparum, the major aetiologic agent of malaria in humans are known. Methods In this study both in vitro and in vivo malaria liver stage models were used to sequence host and pathogen proteoforms. Proteoforms from these diverse models were subjected to mild acid elution (of soluble forms), multi-dimensional fractionation, tandem mass spectrometry, and top-down bioinformatics analysis to identify proteoforms in their intact state. Results These results identify a group of host and malaria liver stage proteoforms that meet a 5% false discovery rate threshold. Conclusions This work provides proof-of-concept for the validity of this mass spectrometry/bioinformatic approach for future studies seeking to reveal malaria liver stage antigens towards vaccine development.

scholarly journals The Plasmodium falciparum circumsporozoite protein produced in Lactococcus lactis is pure and stable

2019 ◽  
Vol 295 (2) ◽  
pp. 403-414 ◽  
Author(s):  
Susheel K. Singh ◽  
Jordan Plieskatt ◽  
Bishwanath Kumar Chourasia ◽  
Vandana Singh ◽  
Judith M. Bolscher ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Lactococcus Lactis ◽  
Malaria Vaccine ◽  
Vaccine Development ◽  
Expression System ◽  
Surface Protein ◽  
Circumsporozoite Protein ◽  
Full Length

The Plasmodium falciparum circumsporozoite protein (PfCSP) is a sporozoite surface protein whose role in sporozoite motility and cell invasion has made it the leading candidate for a pre-erythrocytic malaria vaccine. However, production of high yields of soluble recombinant PfCSP, including its extensive NANP and NVDP repeats, has proven problematic. Here, we report on the development and characterization of a secreted, soluble, and stable full-length PfCSP (containing 4 NVDP and 38 NANP repeats) produced in the Lactococcus lactis expression system. The recombinant full-length PfCSP, denoted PfCSP4/38, was produced initially with a histidine tag and purified by a simple two-step procedure. Importantly, the recombinant PfCSP4/38 retained a conformational epitope for antibodies as confirmed by both in vivo and in vitro characterizations. We characterized this complex protein by HPLC, light scattering, MS analysis, differential scanning fluorimetry, CD, SDS-PAGE, and immunoblotting with conformation-dependent and -independent mAbs, which confirmed it to be both pure and soluble. Moreover, we found that the recombinant protein is stable at both frozen and elevated-temperature storage conditions. When we used L. lactis–derived PfCSP4/38 to immunize mice, it elicited high levels of functional antibodies that had the capacity to modify sporozoite motility in vitro. We concluded that the reported yield, purity, results of biophysical analyses, and stability of PfCSP4/38 warrant further consideration of using the L. lactis system for the production of circumsporozoite proteins for preclinical and clinical applications in malaria vaccine development.

scholarly journals In VitroandIn VivoAntimalarial Activities of T-2307, a Novel Arylamidine

2012 ◽  
Vol 56 (4) ◽  
pp. 2191-2193 ◽  
Author(s):  
Akiko Kimura ◽  
Hiroshi Nishikawa ◽  
Nobuhiko Nomura ◽  
Junichi Mitsuyama ◽  
Shinya Fukumoto ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Body Weight ◽  
Broad Spectrum ◽  
Antimalarial Activity ◽  
Liver Stage ◽  
Rodent Malaria ◽  
Content Type ◽  
Clinically Significant

ABSTRACTT-2307, a novel arylamidine, has been shown to exhibit broad-spectrum antifungal activities against clinically significant pathogens. Here, we evaluated thein vitroandin vivoantimalarial activity of T-2307. The 50% inhibitory concentrations (IC50s) of T-2307 againstPlasmodium falciparumFCR-3 and K-1 strains were 0.47 and 0.17 μM, respectively. T-2307 at 2.5 to 10 mg/kg of body weight/day exhibited activity against blood stage and liver stage parasites in rodent malaria models. In conclusion, T-2307 exhibitedin vitroandin vivoantimalarial activity.

scholarly journals The P. falciparum CSP repeat region contains three distinct epitopes required for protection by antibodies in vivo

2021 ◽  
Vol 17 (11) ◽  
pp. e1010042
Author(s):  
Yevel Flores-Garcia ◽  
Lawrence T. Wang ◽  
Minah Park ◽  
Beejan Asady ◽  
Azza H. Idris ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Monoclonal Antibodies ◽  
Malaria Infection ◽  
Vaccine Development ◽  
Circumsporozoite Protein ◽  
Repeat Region ◽  
Human Mabs ◽  
Necessary And Sufficient

Rare and potent monoclonal antibodies (mAbs) against the Plasmodium falciparum (Pf) circumsporozoite protein (CSP) on infective sporozoites (SPZ) preferentially bind the PfCSP junctional tetrapeptide NPDP or NVDP minor repeats while cross-reacting with NANP major repeats in vitro. The extent to which each of these epitopes is required for protection in vivo is unknown. Here, we assessed whether junction-, minor repeat- and major repeat-preferring human mAbs (CIS43, L9 and 317 respectively) bound and protected against in vivo challenge with transgenic P. berghei (Pb) SPZ expressing either PfCSP with the junction and minor repeats knocked out (KO), or PbCSP with the junction and minor repeats knocked in (KI). In vivo protection studies showed that the junction and minor repeats are necessary and sufficient for CIS43 and L9 to neutralize KO and KI SPZ, respectively. In contrast, 317 required major repeats for in vivo protection. These data establish that human mAbs can prevent malaria infection by targeting three different protective epitopes (NPDP, NVDP, NANP) in the PfCSP repeat region. This report will inform vaccine development and the use of mAbs to passively prevent malaria.

scholarly journals Chemical Attenuation of Plasmodium berghei Sporozoites Induces Sterile Immunity in Mice

2008 ◽  
Vol 76 (3) ◽  
pp. 1193-1199 ◽  
Author(s):  
Lisa A. Purcell ◽  
Stephanie K. Yanow ◽  
Moses Lee ◽  
Terry W. Spithill ◽  
Ana Rodriguez
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Berghei ◽  
Alkylating Agent ◽  
Blood Stage ◽  
Wild Type ◽  
Vaccine Strategy ◽  
Liver Stage ◽  
Stage Development

ABSTRACT Radiation and genetic attenuation of Plasmodium sporozoites are two approaches for whole-organism vaccines that protect against malaria. We evaluated chemical attenuation of sporozoites as an alternative vaccine strategy. Sporozoites were treated with the DNA sequence-specific alkylating agent centanamycin, a compound that significantly affects blood stage parasitemia and transmission of murine malaria and also inhibits Plasmodium falciparum growth in vitro. Here we show that treatment of Plasmodium berghei sporozoites with centanamycin impaired parasite function both in vitro and in vivo. The infection of hepatocytes by sporozoites in vitro was significantly reduced, and treated parasites showed arrested liver stage development. Inoculation of mice with sporozoites that were treated in vitro with centanamycin failed to produce blood stage infections. Furthermore, BALB/c and C57BL/6 mice vaccinated with treated sporozoites were protected against subsequent challenge with wild-type sporozoites. Our findings demonstrate that chemically attenuated sporozoites could be a viable alternative for the production of an effective liver stage vaccine for malaria.

scholarly journals Human Antibodies against Plasmodium falciparumLiver-Stage Antigen 3 Cross-React with Plasmodium yoelii Preerythrocytic-Stage Epitopes and Inhibit Sporozoite Invasion In Vitro and In Vivo

2001 ◽  
Vol 69 (6) ◽  
pp. 3845-3852 ◽  
Author(s):  
Karima Brahimi ◽  
Edgar Badell ◽  
Jean-Pierre Sauzet ◽  
Lbachir BenMohamed ◽  
Pierre Daubersies ◽  
...  
Keyword(s):  
Peripheral Blood Lymphocytes ◽  
Plasmodium Yoelii ◽  
T Cell Epitopes ◽  
Liver Stage ◽  
Human Antibodies ◽  
In Vitro Invasion ◽  
Synthetic Polypeptides ◽  
Mouse Hepatocytes

ABSTRACT The Plasmodium falciparum liver-stage antigen 3 (LSA3), a recently identified preerythrocytic antigen, induces protection against malaria in chimpanzees. Using antibodies from individuals with hyperimmunity to malaria affinity purified on recombinant or synthetic polypeptides of LSA3, we identified four non-cross-reactive B-cell epitopes in Plasmodium yoelii preerythrocytic stages. On sporozoites the P. yoelii protein detected has a molecular mass similar to that of LSA3. T-cell epitopes cross-reacting withP. yoelii were also demonstrated using peripheral blood lymphocytes from LSA3-immunized chimpanzees. In contrast, no cross-reactive epitopes were found in Plasmodium berghei. LSA3-specific human antibodies exerted up to 100% inhibition of in vitro invasion of P. yoelii sporozoites into mouse hepatocytes. This strong in vitro activity was reproduced in vivo by passive transfer of LSA3 antibodies. These results indicate that the homologous epitopes may be biologically functional and suggest that P. yoelii could be used as a model to assess the antisporozoite activity of anti-LSA3 antibodies.

scholarly journals Chemical Attenuation in the Development of a Whole-Organism Malaria Vaccine

2017 ◽  
Vol 85 (7) ◽  
Author(s):  
Amber I. Raja ◽  
Danielle I. Stanisic ◽  
Michael F. Good
Keyword(s):  
Subunit Vaccine ◽  
Malaria Parasite ◽  
Malaria Vaccine ◽  
Vaccine Development ◽  
Liver Stage ◽  
Content Type ◽  
Vaccine Candidates ◽  
Limited Efficacy

ABSTRACT Malaria vaccine development has been dominated by the subunit approach; however, many subunit vaccine candidates have had limited efficacy in settings of malaria endemicity. As our search for an efficacious malaria vaccine continues, the development of a whole-organism vaccine is now receiving much scrutiny. One strategy currently being explored in the development of a whole-organism vaccine involves chemical attenuation of the malaria parasite. In vivo and in vitro chemical attenuation of both liver-stage and blood-stage Plasmodium parasites has been investigated. Here, we discuss both approaches of chemical attenuation in the development of a whole-organism vaccine against malaria.

scholarly journals Design of T cell epitope-based vaccine candidate for SARS-CoV-2 targeting nucleocapsid and spike protein escape variants

2021 ◽  
Author(s):  
Gabriel Jabbour ◽  
Samantha Rego ◽  
Vincent Nguyenkhoa ◽  
Sivanesan Dakshanamurthy
Keyword(s):  
T Cell ◽  
Vaccine Development ◽  
Cell Epitope ◽  
Epitope Prediction ◽  
T Cell Epitopes ◽  
Clinical Predictors ◽  
Nucleocapsid Proteins ◽  
Global Concern

AbstractThe current COVID-19 pandemic continues to spread and devastate in the absence of effective treatments, warranting global concern and action. Despite progress in vaccine development, the rise of novel, increasingly infectious SARS-CoV-2 variants makes it clear that our response to the virus must continue to evolve along with it. The use of immunoinformatics provides an opportunity to rapidly and efficiently expand the tools at our disposal to combat the current pandemic and prepare for future outbreaks through epitope-based vaccine design. In this study, we validated and compared the currently available epitope prediction tools, and then used the best tools to predict T cell epitopes from SARS-CoV-2 spike and nucleocapsid proteins for use in an epitope-based vaccine. We combined the mouse MHC affinity predictor and clinical predictors such as HLA affinity, immunogenicity, antigenicity, allergenicity, toxicity and stability to select the highest quality CD8 and CD4 T cell epitopes for the common SARS-CoV-2 variants of concern suitable for further preclinical studies. We also identified variant-specific epitopes to more precisely target the Alpha, Beta, Gamma, Delta, Cluster 5 and US variants. We then modeled the 3D structures of our top 4 N and S epitopes to investigate the molecular interaction between peptide-MHC and peptide-MHC-TCR complexes. Following in vitro and in vivo validation, the epitopes identified by this study may be used in an epitope-based vaccine to protect across all current variants, as well as in variant-specific booster shots to target variants of concern. Immunoinformatics tools allowed us to efficiently predict epitopes in silico most likely to prove effective in vivo, providing a more streamlined process for vaccine development in the context of a rapidly evolving pandemic.

scholarly journals Immunogenic Evaluation of Ribosomal P-Protein Antigen P0, P1, and P2 and Pentameric Protein Complex P0-(P1-P2)2 of Plasmodium falciparum in a Mouse Model

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Agnieszka Szuster-Ciesielska ◽  
Leszek Wawiórka ◽  
Dawid Krokowski ◽  
Nikodem Grankowski ◽  
Łukasz Jarosz ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Mouse Model ◽  
Cellular Response ◽  
Vaccine Development ◽  
Control Level ◽  
Complex Life Cycle ◽  
Immune Memory ◽  
P Protein

Malaria remains one the most infectious and destructive protozoan diseases worldwide. Plasmodium falciparum, a protozoan parasite with a complex life cycle and high genetic variability responsible for the difficulties in vaccine development, is implicated in most malaria-related deaths. In the course of study, we prepared a set of antigens based on P-proteins from P. falciparum and determined their immunogenicity in an in vivo assay on a mouse model. The pentameric complex P0-(P1-P2)2 was prepared along with individual P1, P2, and P0 antigens. We determined the level of cellular- and humoral-type immunological response followed by development of specific immunological memory. We have shown that the number of Tc cells increased significantly after the first immunization with P2 and after the second immunization with P1 and P0-(P1-P2)2, which highly correlated with the number of Th1 cells. P0 appeared as a poor inducer of cellular response. After the third boost with P1, P2, or P0-(P1-P2)2, the initially high cellular response dropped to the control level accompanied by elevation of the number of activated Treg cells and a high level of suppressive TGF-β. Subsequently, the humoral response against the examined antigens was activated. Although the titers of specific IgG were increasing during the course of immunization for all antigens used, P2 and P0-(P1-P2)2 were found to be significantly stronger than P1 and P0. A positive correlation between the Th2 cell abundance and the level of IL-10 was observed exclusively after immunization with P0-(P1-P2)2. An in vitro exposure of spleen lymphocytes from the immunized mice especially to the P1, P2, and P0-(P1-P2)2 protein caused 2-3-fold higher cell proliferation than that in the case of lymphocytes from the nonimmunized animals, suggesting development of immune memory. Our results demonstrate for the first time that the native-like P-protein pentameric complex represents much stronger immune potential than individual P-antigens.

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

scholarly journals Stage-dependent effect of deferoxamine on growth of Plasmodium falciparum in vitro

Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1250-1255 ◽  
Author(s):  
S Whitehead ◽  
TE Peto
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Antimalarial Activity ◽  
Clinical Malaria ◽  
Inhibitory Effect ◽  
Parasite Development ◽  
And Control ◽  
Speed Of Onset

Abstract Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.

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