scholarly journals Predicting transmission blocking potential of anti-malarial compounds in the Mosquito Feeding Assay using Plasmodium falciparum Male Gamete Inhibition Assay

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Gonzalo Colmenarejo ◽  
Sonia Lozano ◽  
Carolina González-Cortés ◽  
David Calvo ◽  
Juliana Sanchez-Garcia ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Male Gamete ◽  
Inhibition Assay ◽  
Feeding Assay ◽  
Transmission Blocking

scholarly journals Plasmodium falciparum protein Pfs16 is a target for transmission-blocking antimalarial drug development

2021 ◽  
Author(s):  
Sabrina Yahiya ◽  
Charlie N Saunders ◽  
Ursula Straschil ◽  
Oliver J Fischer ◽  
Ainoa Rueda-Zubiaurre ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Parasitophorous Vacuole ◽  
Male Gamete ◽  
Immunoblot Analysis ◽  
Transmission Blocking ◽  
Lead Compounds ◽  
Phenotypic Screen ◽  
Starting Point ◽  
Cellular Target ◽  
Affinity Labelling

Phenotypic cell-based screens are critical to the discovery of new antimalarial lead compounds. However, identification and validation of cellular targets of lead compounds is required following discovery in a phenotypic screen. We recently discovered a Plasmodium transmission-blocking N-((4-hydroxychroman-4-yl)methyl)-sulfonamide (N-4HCS) compound, DDD01035881, in a phenotypic screen. DDD01035881 and its potent derivatives have been shown to block Plasmodium male gamete formation (microgametogenesis) with nanomolar activity. Here, we synthesised a photoactivatable N-4HCS derivative, probe 2, to identify the N-4HCS cellular target. Using probe 2 in photo-affinity labelling coupled with mass spectrometry, we identified the 16 kDa Plasmodium falciparum parasitophorous vacuole membrane protein Pfs16 as the likely cellular target of the N-4HCS series. Further validating Pfs16 as the cellular target of the N-4HCS series, the Cellular Thermal Shift Assay (CETSA) confirmed DDD01035881 stabilised Pfs16 in lysate from activated mature gametocytes. Additionally, photo-affinity labelling combined with in-gel fluorescence and immunoblot analysis confirmed the N-4HCS series interacted with Pfs16. High-resolution, widefield fluorescence and electron microscopy of N-4HCS-inhibited parasites was found to result in a cell morphology entirely consistent with targeted gene disruption of Pfs16. Taken together, these data strongly implicate Pfs16 as the target of DDD01035881 and establish the N-4HCS scaffold family as a powerful starting point from which future transmission-blocking antimalarials can be developed.

scholarly journals Gametocytes from K13 Propeller Mutant Plasmodium falciparum Clinical Isolates Demonstrate Reduced Susceptibility to Dihydroartemisinin in the Male Gamete Exflagellation Inhibition Assay

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
Sonia Lozano ◽  
Pablo Gamallo ◽  
Carolina González-Cortés ◽  
Jesús-Luís Presa Matilla ◽  
Rick M. Fairhurst ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Male Gamete ◽  
Clinical Isolates ◽  
Inhibition Assay ◽  
Wild Type ◽  
Content Type ◽  
Gamete Formation

ABSTRACT Mutations in the kelch propeller domain (K13 propeller) of Plasmodium falciparum parasites from Southeast Asia are associated with reduced susceptibility to artemisinin. We exposed in vitro-cultured stage V gametocytes from Cambodian K13 propeller mutant parasites to dihydroartemisinin and evaluated the inhibition of male gamete formation in an in vitro exflagellation inhibition assay (EIA). Gametocytes with the R539T and C580Y K13 propeller alleles were less susceptible to dihydroartemisinin and had significantly higher 50% inhibitory concentrations (IC50s) than did gametocytes with wild-type alleles.

scholarly journals Functional Comparison of Plasmodium falciparum Transmission-Blocking Vaccine Candidates by the Standard Membrane-Feeding Assay

2013 ◽  
Vol 81 (12) ◽  
pp. 4377-4382 ◽  
Author(s):  
Kazutoyo Miura ◽  
Eizo Takashima ◽  
Bingbing Deng ◽  
Gregory Tullo ◽  
Ababacar Diouf ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Recombinant Proteins ◽  
The Other ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Feeding Assay ◽  
Transmission Blocking ◽  
Content Type ◽  
Membrane Feeding ◽  
Membrane Feeding Assay

ABSTRACTRecently, there has been a renewed interest in the development of transmission-blocking vaccines (TBV) againstPlasmodium falciparummalaria. While several candidate TBVs have been reported, studies directly comparing them in functional assays are limited. To this end, recombinant proteins of TBV candidates Pfs25, Pfs230, and PfHAP2 were expressed in the wheat germ cell-free expression system. Outbred CD-1 mice were immunized twice with the antigens. Two weeks after the second immunization, IgG levels were measured by enzyme-linked immunosorbent assay (ELISA), and IgG functionality was assessed by the standard membrane-feeding assay (SMFA) using culturedP. falciparumNF54 gametocytes andAnopheles stephensimosquitoes. All three recombinant proteins elicited similar levels of antigen-specific IgG judged by ELISA. When IgGs purified from pools of immune serum were tested at 0.75 mg/ml in the SMFA, all three IgGs showed 97 to 100% inhibition in oocyst intensity compared to control IgG. In two additional independent SMFA evaluations, anti-Pfs25, anti-Pfs230, and anti-PfHAP2 IgGs inhibited oocyst intensity in a dose-dependent manner. When all three data sets were analyzed, anti-Pfs25 antibody showed significantly higher inhibition than the other two antibodies (P< 0.001 for both), while there was no significant difference between the other two (P= 0.15). A proportion of plasma samples collected from adults living in an area of malaria endemicity in Mali recognized Pfs230 and PfHAP2. This is the first study showing that the HAP2 protein ofP. falciparumcan induce transmission-blocking antibody. The current study supports the possibility of using this system for a comparative study with multiple TBV candidates.

scholarly journals A Plant-Produced Pfs25 VLP Malaria Vaccine Candidate Induces Persistent Transmission Blocking Antibodies against Plasmodium falciparum in Immunized Mice

PLoS ONE ◽  
2013 ◽  
Vol 8 (11) ◽  
pp. e79538 ◽  
Author(s):  
R. Mark Jones ◽  
Jessica A. Chichester ◽  
Vadim Mett ◽  
Jennifer Jaje ◽  
Stephen Tottey ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Vaccine ◽  
Vaccine Candidate ◽  
Transmission Blocking ◽  
Malaria Vaccine Candidate ◽  
Blocking Antibodies

scholarly journals Activity of Clinically Relevant Antimalarial Drugs on Plasmodium falciparum Mature Gametocytes in an ATP Bioluminescence “Transmission Blocking” Assay

PLoS ONE ◽  
2012 ◽  
Vol 7 (4) ◽  
pp. e35019 ◽  
Author(s):  
Joël Lelièvre ◽  
Maria Jesus Almela ◽  
Sonia Lozano ◽  
Celia Miguel ◽  
Virginia Franco ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Antimalarial Drugs ◽  
Transmission Blocking ◽  
Atp Bioluminescence ◽  
Blocking Assay

scholarly journals DSM265 at 400 Milligrams Clears Asexual Stage Parasites but Not Mature Gametocytes from the Blood of Healthy Subjects Experimentally Infected with Plasmodium falciparum

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
Katharine A. Collins ◽  
Thomas Rückle ◽  
Suzanne Elliott ◽  
Louise Marquart ◽  
Emma Ballard ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Pharmacodynamic Modeling ◽  
Dihydroorotate Dehydrogenase ◽  
Transmission Blocking ◽  
Content Type ◽  
Blocking Activity ◽  
Cutaneous Rash ◽  
Phase 1B ◽  
Study Support ◽  
Previous Phase

ABSTRACT DSM265 is a novel antimalarial drug in clinical development that acts as a selective inhibitor of Plasmodium dihydroorotate dehydrogenase. In a previous phase 1b study, a single 150-mg dose of DSM265 showed partial efficacy against experimentally induced blood-stage Plasmodium falciparum malaria (IBSM). Pharmacokinetic/pharmacodynamic modeling predicted a human efficacious dose of 340 mg. The primary objectives of the current study were to determine the safety and efficacy of a single oral 400-mg dose of DSM265 against P. falciparum in the IBSM model. Eight healthy participants were inoculated intravenously with 2,800 parasites and treated with DSM265 7 days later. Unexpectedly, one participant did not develop parasitemia during the study. All other participants developed parasitemia, with the complete clearance of asexual parasites occurring following DSM265 treatment. All seven subjects also became gametocytemic. The secondary objectives were to investigate the gametocytocidal and transmission-blocking activity of a second 400-mg dose of DSM265, which was administered 23 days after inoculation. Gametocytes were not cleared by the second dose of DSM265, and transmission-blocking activity could not be determined due to low gametocyte densities. Three DSM265-related adverse events occurred, including a cutaneous rash in one subject on the day of the second DSM265 dose. The results obtained in this study support the prediction of the efficacious dose of DSM265 and provide further evidence that DSM265 is generally safe and well tolerated. In addition, this study confirms preclinical data indicating that DSM265 permits the development and maturation of gametocytes and does not clear mature circulating gametocytes. (This study has been registered at ClinicalTrials.gov under identifier NCT02573857.)

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