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Alkema M, Smit MJ, Marin-Mogollon C, Totté K, Teelen K, van Gemert GJ, van de Vegte-Bolmer M, Mordmüller BG, Reimer JM, Lövgren-Bengtsson KL, Sauerwein RW, Bousema T, Plieskatt J, Theisen M, Jore MM, McCall MBB. A Pfs48/45-based vaccine to block Plasmodium falciparum transmission: phase 1, open-label, clinical trial. BMC Med 2024; 22:170. [PMID: 38649867 PMCID: PMC11036667 DOI: 10.1186/s12916-024-03379-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 04/02/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND The stalling global progress in malaria control highlights the need for novel tools for malaria elimination, including transmission-blocking vaccines. Transmission-blocking vaccines aim to induce human antibodies that block parasite development in the mosquito and mosquitoes becoming infectious. The Pfs48/45 protein is a leading Plasmodium falciparum transmission-blocking vaccine candidate. The R0.6C fusion protein, consisting of Pfs48/45 domain 3 (6C) and the N-terminal region of P. falciparum glutamate-rich protein (R0), has previously been produced in Lactococcus lactis and elicited functional antibodies in rodents. Here, we assess the safety and transmission-reducing efficacy of R0.6C adsorbed to aluminium hydroxide with and without Matrix-M™ adjuvant in humans. METHODS In this first-in-human, open-label clinical trial, malaria-naïve adults, aged 18-55 years, were recruited at the Radboudumc in Nijmegen, the Netherlands. Participants received four intramuscular vaccinations on days 0, 28, 56 and 168 with either 30 µg or 100 µg of R0.6C and were randomised for the allocation of one of the two different adjuvant combinations: aluminium hydroxide alone, or aluminium hydroxide combined with Matrix-M1™ adjuvant. Adverse events were recorded from inclusion until 84 days after the fourth vaccination. Anti-R0.6C and anti-6C IgG titres were measured by enzyme-linked immunosorbent assay. Transmission-reducing activity of participants' serum and purified vaccine-specific immunoglobulin G was assessed by standard membrane feeding assays using laboratory-reared Anopheles stephensi mosquitoes and cultured P. falciparum gametocytes. RESULTS Thirty-one participants completed four vaccinations and were included in the analysis. Administration of all doses was safe and well-tolerated, with one related grade 3 adverse event (transient fever) and no serious adverse events occurring. Anti-R0.6C and anti-6C IgG titres were similar between the 30 and 100 µg R0.6C arms, but higher in Matrix-M1™ arms. Neat participant sera did not induce significant transmission-reducing activity in mosquito feeding experiments, but concentrated vaccine-specific IgGs purified from sera collected two weeks after the fourth vaccination achieved up to 99% transmission-reducing activity. CONCLUSIONS R0.6C/aluminium hydroxide with or without Matrix-M1™ is safe, immunogenic and induces functional Pfs48/45-specific transmission-blocking antibodies, albeit at insufficient serum concentrations to result in transmission reduction by neat serum. Future work should focus on identifying alternative vaccine formulations or regimens that enhance functional antibody responses. TRIAL REGISTRATION The trial is registered with ClinicalTrials.gov under identifier NCT04862416.
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Affiliation(s)
- M Alkema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - M J Smit
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - C Marin-Mogollon
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - K Totté
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - K Teelen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - G J van Gemert
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - M van de Vegte-Bolmer
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - B G Mordmüller
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | | | - R W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
- Present Address: TropIQ Health Sciences, Nijmegen, the Netherlands
| | - T Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - J Plieskatt
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - M Theisen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - M M Jore
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - M B B McCall
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands.
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Abstract
Vaccine efficacy and prophylactic treatment of infections are tested best when the vaccinated or treated individual is challenged through deliberate infection with the respective pathogen. However, this trial design calls for particular ethical caution. Awareness of the history of challenge trials is indispensable, including trials that were problematic or even connected to abuse. We briefly introduce historical aspects of experimental infections in humans and the ethical debate around them and give estimates of the numbers of volunteers participating in human experimental infection models. Challenge models can offer a great chance and benefit for the development of medical interventions to fight infectious diseases, but only when they are appropriately controlled and regulated.
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Affiliation(s)
- W G Metzger
- Institute for Tropical Medicine, German Center for Infection Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - H-J Ehni
- Institute for Ethics and History of Medicine, Eberhard Karls University Tübingen, Tübingen, Germany
| | - P G Kremsner
- Institute for Tropical Medicine, German Center for Infection Research, Eberhard Karls University Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - B G Mordmüller
- Institute for Tropical Medicine, German Center for Infection Research, Eberhard Karls University Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
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Brandts CH, Mordmüller BG, Lehman LG, Kremsner PG. [The dual role of tumor necrosis factor (TNF) during a malarial attack]. Sante 1997; 7:271-4. [PMID: 9410454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The roles of the various factors implicated in the pathogenesis of severe malaria are not well understood. Tumor necrosis factor (TNF), a cytokine produced mainly by macrophages, seems to play a crucial role in both the host's defence against the parasite and the development of severe complications. This review investigates the dual role of TNF in acute malaria, summarizing current knowledge of the beneficial and detrimental effects of this molecule. Recent work has suggested a possible explanation for this dualism, involving a complex interaction between TNF and its soluble receptors.
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Affiliation(s)
- C H Brandts
- Laboratoire de recherches, Hôpital Albert-Schweitzer, Lambaréné, Gabon
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Mordmüller BG, Metzger WG, Juillard P, Brinkman BM, Verweij CL, Grau GE, Kremsner PG. Tumor necrosis factor in Plasmodium falciparum malaria: high plasma level is associated with fever, but high production capacity is associated with rapid fever clearance. Eur Cytokine Netw 1997; 8:29-35. [PMID: 9110145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the present study, we investigated 91 patients with Plasmodium falciparum malaria of different severity in a highly endemic area. Patients were examined at least twice daily until clearance of parasites and fever. Plasma cytokine concentrations without and after ex vivo PHA stimulation of whole blood were determined. On admission we found elevated plasma concentrations of TNF, IFN-gamma, and IL-10 compared to levels during and after chemotherapy. Plasma TNF levels on admission were significantly different between patients with severe and mild malaria (differentiated in schoolchildren and adults). The PHA elicited TNF production capacity of peripheral blood leucocytes was suppressed during the acute phase of malaria. High TNF production capacity was associated with faster fever clearance and parasite clearance and, in patients with severe malaria, with higher blood glucose levels. In conclusion we observed circulating TNF concentrations in malaria patients dependent on the severity of disease, which is itself dependent on age, and an association of a high TNF production capacity with parameters for accelerated cure and good prognosis.
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Affiliation(s)
- B G Mordmüller
- Research Laboratory, Albert-Schweitzer-Hospital, Lambaréné, Gabon
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