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Friedman-Klabanoff DJ, Berry AA, Travassos MA, Shriver M, Cox C, Butts J, Lundeen JS, Strauss KA, Joshi S, Shrestha B, Mo AX, Nomicos EYH, Deye GA, Regules JA, Bergmann-Leitner ES, Pasetti MF, Laurens MB. Recombinant full-length Plasmodium falciparum circumsporozoite protein-based vaccine adjuvanted with GLA-LSQ: Results of Phase 1 testing with malaria challenge. J Infect Dis 2024:jiae062. [PMID: 38330357 DOI: 10.1093/infdis/jiae062] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 01/29/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024] Open
Abstract
INTRODUCTION Malaria is preventable yet causes >600,000 deaths annually. RTS, S, the first marketed malaria vaccine, has modest efficacy, but improvements are needed for eradication. METHODS We conducted an open-label, dose escalation Phase 1 study of a recombinant, full-length circumsporozoite protein vaccine (rCSP) administered with adjuvant GLA-LSQ on days 1, 29, and 85 or 1 and 490 to healthy, malaria-naïve adults. Primary endpoints were safety and reactogenicity. Secondary endpoints were antibody responses and Plasmodium falciparum parasitemia after homologous controlled human malaria infection (CHMI). RESULTS Participants were enrolled into four groups receiving rCSP/GLA-LSQ: 10 µg x 3 (n = 20), 30 µg x 3 (n = 10), 60 µg x 3 (n = 10) or 60 µg x 2 (n = 9); ten participants received 30 µg rCSP alone x 3; and six infectivity controls. Participants experienced no serious adverse events. Rates of solicited and unsolicited adverse events were similar among groups. All 26 participants who underwent CHMI 28 days after final vaccinations developed malaria. Increasing vaccine doses induced higher IgG titers, but did not achieve previously established RTS, S benchmarks. CONCLUSIONS rCSP/GLA-LSQ had favorable safety results. However, tested regimens did not induce protective immunity. Further investigation could assess if adjuvant or schedule adjustments improve efficacy. TRIAL REGISTRATION ClinicalTrials.gov Identifier NCT03589794.
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Affiliation(s)
- DeAnna J Friedman-Klabanoff
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Andrea A Berry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mark A Travassos
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Mallory Shriver
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | | | | | - Kathleen A Strauss
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Sudhaunshu Joshi
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Biraj Shrestha
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Annie X Mo
- Parasitology and International Programs Branch, Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Effie Y H Nomicos
- Parasitology and International Programs Branch, Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Gregory A Deye
- Parasitology and International Programs Branch, Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Jason A Regules
- Biologics Research & Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Elke S Bergmann-Leitner
- Biologics Research & Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Marcela F Pasetti
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Matthew B Laurens
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Thomson-Luque R, Stabler TC, Fürle K, Silva JC, Daubenberger C. Plasmodium falciparum merozoite surface protein 1 as asexual blood stage malaria vaccine candidate. Expert Rev Vaccines 2024; 23:160-173. [PMID: 38100310 DOI: 10.1080/14760584.2023.2295430] [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] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/12/2023] [Indexed: 12/17/2023]
Abstract
INTRODUCTION Malaria represents a public health challenge in tropical and subtropical regions, and currently deployed control strategies are likely insufficient to drive elimination of malaria. Development and improvement of malaria vaccines might be key to reduce disease burden. Vaccines targeting asexual blood stages of the parasite have shown limited efficacy when studied in human trials conducted over the past decades. AREAS COVERED Vaccine candidates based on the merozoite surface protein 1 (MSP1) were initially envisioned as one of the most promising approaches to provide immune protection against asexual blood-stage malaria. Successful immunization studies in monkey involved the use of the full-length MSP1 (MSP1FL) as vaccine construct. Vaccines using MSP1FL for immunization have the potential benefit of including numerous conserved B-cell and T-cell epitopes. This could result in improved parasite strain-transcending, protective immunity in the field. We review outcomes of clinical trials that utilized a variety of MSP1 constructs and formulations, including MSP1FL, either alone or in combination with other antigens, in both animal models and humans. EXPERT OPINION Novel approaches to analyze breadth and magnitude of effector functions of MSP1-targeting antibodies in volunteers undergoing experimental vaccination and controlled human malaria infection will help to define correlates of protective immunity.
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Affiliation(s)
- Richard Thomson-Luque
- Centre for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
- Sumaya-Biotech GmbH & Co. KG Heidelberg, Germany
| | - Thomas C Stabler
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Basel Basel, Switzerland
- Swiss Tropical and Public Health Institute Allschwil, Switzerland
| | - Kristin Fürle
- Centre for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (GHTM IHMT, UNL), Lisbon, Portugal
| | - Claudia Daubenberger
- University of Basel Basel, Switzerland
- Swiss Tropical and Public Health Institute Allschwil, Switzerland
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Woolley SD, Grigg MJ, Marquart L, Gower J, Piera K, Nair AS, Amante FM, Rajahram GS, William T, Frazer DM, Chalon S, McCarthy JS, Anstey NM, Barber BE. Longitudinal changes in iron homeostasis in human experimental and clinical malaria. medRxiv 2023:2023.12.19.23300265. [PMID: 38196596 PMCID: PMC10775340 DOI: 10.1101/2023.12.19.23300265] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Background The interaction between iron deficiency and malaria is incompletely understood. We evaluated longitudinal changes in iron homeostasis in volunteers enrolled in malaria volunteer infection studies (VIS) and in Malaysian patients with falciparum and vivax malaria. Methods We retrieved samples and associated data from 55 participants enrolled in malaria VIS, and 171 malaria patients and 30 healthy controls enrolled in clinical studies in Malaysia. Ferritin, hepcidin, erythropoietin, and soluble transferrin receptor (sTfR) were measured by ELISA. Results In the VIS, participants' parasitaemia was correlated with baseline mean corpuscular volume (MCV), but not iron status (ferritin, hepcidin or sTfR). Ferritin, hepcidin and sTfR all increased during the VIS. Ferritin and hepcidin normalised by day 28, while sTfR remained elevated. In VIS participants, baseline iron status (ferritin) was associated with post-treatment increases in liver transaminase levels. In Malaysian malaria patients, hepcidin and ferritin were elevated on admission compared to healthy controls, while sTfR increased following admission. Hepcidin normalised by day 28; however, ferritin and sTfR both remained elevated 4 weeks following admission. Conclusion Our findings demonstrate that parasitaemia is associated with an individual's MCV rather than iron status. The persistent elevation in sTfR 4 weeks post-infection in both malaria VIS and clinical malaria may reflect a causal link between malaria and iron deficiency.
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Affiliation(s)
- Stephen D Woolley
- Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Clinical Sciences Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Academic Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, United Kingdom
| | - Matthew J Grigg
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
| | - Louise Marquart
- Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- School of Public Health, University of Queensland, Brisbane, Australia
| | - Jeremy Gower
- Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Kim Piera
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Arya Sheela Nair
- Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Fiona M Amante
- Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Giri S Rajahram
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
- Department of Medicine, Queen Elizabeth II Hospital, Kota Kinabalu, Malaysia
- Clinical Research Centre, Queen Elizabeth Hospital, Kota Kinabalu, Malaysia
| | - Timothy William
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
- Department of Medicine, Queen Elizabeth II Hospital, Kota Kinabalu, Malaysia
- Subang Jaya Medical Centre, Subang Jaya, Malaysia
| | - David M Frazer
- Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | | | - James S McCarthy
- Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Victorian Infectious Diseases Institute, Peter Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Nicholas M Anstey
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
| | - Bridget E Barber
- Infection and Inflammation Program, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
- Infectious Diseases Society Kota Kinabalu Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Malaysia
- Infectious Diseases Department, Royal Brisbane and Women's Hospital, Brisbane, Australia
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Chavtur C, Staubus WJ, Ho M, Hergott DEB, Seilie AM, Healy S, Duffy P, Jackson L, Talley A, Kappe SHI, Hoffman SL, Richie TL, Kublin JG, Chang M, Murphy SC. Plasmodium 18S Ribosomal RNA Biomarker Clearance After Food and Drug Administration-Approved Antimalarial Treatment in Controlled Human Malaria Infection Trials. Open Forum Infect Dis 2023; 10:ofad202. [PMID: 37265668 PMCID: PMC10230565 DOI: 10.1093/ofid/ofad202] [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] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/12/2023] [Indexed: 06/03/2023] Open
Abstract
Background Sensitive molecular assays, such as quantitative reverse-transcription polymerase chain reaction (qRT-PCR) of Plasmodium 18S ribosomal RNA (rRNA), are increasingly the primary method of detecting infections in controlled human malaria infection (CHMI) trials. However, thick blood smears (TBSs) remain the main method for confirming clearance of parasites after curative treatment, in part owing to uncertainty regarding biomarker clearance rates. Methods For this analysis, 18S rRNA qRT-PCR data were compiled from 127 Plasmodium falciparum-infected participants treated with chloroquine or atovaquone-proguanil in 6 CHMI studies conducted in Seattle, Washington, over the past decade. A survival analysis approach was used to compare biomarker and TBS clearance times among studies. The effect of the parasite density at which treatment was initiated on clearance time was estimated using linear regression. Results The median time to biomarker clearance was 3 days (interquartile range, 3-5 days), while the median time to TBS clearance was 1 day (1-2 days). Time to biomarker clearance increased with the parasite density at which treatment was initiated. Parasite density did not have a significant effect on TBS clearance. Conclusions The Plasmodium 18S rRNA biomarker clears quickly and can be relied on to confirm the adequacy of Food and Drug Administration-approved treatments in CHMI studies at nonendemic sites.
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Affiliation(s)
- Chris Chavtur
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Weston J Staubus
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Mabel Ho
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Dianna E B Hergott
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, USA
| | - Annette M Seilie
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Sara Healy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Patrick Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Lisa Jackson
- Kaiser Permanente Washington Health Research Institute, Seattle, Washington, USA
| | | | - Stefan H I Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, Washington, USA
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | | | | | - James G Kublin
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Ming Chang
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
| | - Sean C Murphy
- Malaria Molecular Diagnostic Laboratory, Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington, Seattle, Washington, USA
- Seattle Malaria Clinical Trials Center, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
- Department of Microbiology, University of Washington, Seattle, Washington, USA
- Department of Laboratories, Seattle Children's Hospital, Seattle, Washington, USA
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5
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de Jong GM, Yap XZ, Walk J, Dik WA, McCall MBB, van Genderen PJJ, van Hellemond JJ, Verbon A, Sauerwein RW. Baseline TGF-β correlates with protection after immunization with Plasmodium falciparum sporozoites in the Controlled Human Malaria Infection model. Immunol Lett 2023; 258:20-23. [PMID: 37075916 DOI: 10.1016/j.imlet.2023.04.005] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/31/2023] [Accepted: 04/15/2023] [Indexed: 04/21/2023]
Abstract
BACKGROUND Here we assessed a possible relationship between baseline TGF-β concentrations and acquisition of sterile immunity after Plasmodium falciparum sporozoite immunization. METHODS TGF-β concentrations were determined in samples of 65 malaria-naive volunteers in 4 studies either prior to and after challenge infection, or prior to and after first immunizing infection under chemoprophylaxis with P. falciparum sporozoites. RESULTS High baseline TGF-β concentrations were associated with rapid acquisition of sterile protection (p=0.028). CONCLUSION Baseline TGF-β concentrations predict the efficiency of acquisition of sterile immunity following sporozoite immunisation and may represent a steady-state regulatory mechanism to keep in check immune systems with a low threshold for activation.
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Affiliation(s)
- G M de Jong
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, 6500HB, The Netherlands
| | - X Z Yap
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, 6500HB, The Netherlands
| | - J Walk
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, 6500HB, The Netherlands
| | - W A Dik
- Department of Immunology, Laboratory Medical Immunology, Erasmus MC University Medical Center, Rotterdam, 3015GD, the Netherlands
| | - M B B McCall
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, 6500HB, The Netherlands
| | - P J J van Genderen
- Department of Medical Microbiology & Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, 3015 GD, The Netherlands
| | - J J van Hellemond
- Department of Medical Microbiology & Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, 3015 GD, The Netherlands
| | - A Verbon
- Department of Medical Microbiology & Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, 3015 GD, The Netherlands
| | - R W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, 6500HB, The Netherlands.
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Palacpac NMQ, Tiono AB, Mordmüller B, Tsuboi T. Editorial: Puzzle pieces from malaria vaccine clinical trials. Front Immunol 2023; 14:1138763. [PMID: 36793714 PMCID: PMC9923721 DOI: 10.3389/fimmu.2023.1138763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Affiliation(s)
- Nirianne Marie Q. Palacpac
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan,*Correspondence: Nirianne Marie Q. Palacpac,
| | - Alfred B. Tiono
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Benjamin Mordmüller
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Takafumi Tsuboi
- Division of Cell-Free Sciences, Proteo-Science Center, Ehime University, Matsuyama, Japan
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Roobsoong W, Yadava A, Draper SJ, Minassian AM, Sattabongkot J. The challenges of Plasmodium vivax human malaria infection models for vaccine development. Front Immunol 2023; 13:1006954. [PMID: 36685545 PMCID: PMC9849360 DOI: 10.3389/fimmu.2022.1006954] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 12/09/2022] [Indexed: 01/07/2023] Open
Abstract
Controlled Human Malaria Infection models (CHMI) have been critical to advancing new vaccines for malaria. Stringent and safe preparation of a challenge agent is key to the success of any CHMI. Difficulty producing the Plasmodium vivax parasite in vitro has limited production of qualified parasites for CHMI as well as the functional assays required to screen and down-select candidate vaccines for this globally distributed parasite. This and other challenges to P. vivax CHMI (PvCHMI), including scientific, logistical, and ethical obstacles, are common to P. vivax research conducted in both non-endemic and endemic countries, with additional hurdles unique to each. The challenges of using CHMI for P. vivax vaccine development and evaluation, lessons learned from previous and ongoing clinical trials, and the way forward to effectively perform PvCHMI to support vaccine development, are discussed.
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Affiliation(s)
- Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Anjali Yadava
- Biologics Research & Development, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Simon J. Draper
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | | | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Murphy SC, Vaughan AM, Kublin JG, Fishbauger M, Seilie AM, Cruz KP, Mankowski T, Firat M, Magee S, Betz W, Kain H, Camargo N, Haile MT, Armstrong J, Fritzen E, Hertoghs N, Kumar S, Sather DN, Pinder LF, Deye GA, Galbiati S, Geber C, Butts J, Jackson LA, Kappe SH. A genetically engineered Plasmodium falciparum parasite vaccine provides protection from controlled human malaria infection. Sci Transl Med 2022; 14:eabn9709. [PMID: 36001680 PMCID: PMC10423335 DOI: 10.1126/scitranslmed.abn9709] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Genetically engineered live Plasmodium falciparum sporozoites constitute a potential platform for creating consistently attenuated, genetically defined, whole-parasite vaccines against malaria through targeted gene deletions. Such genetically attenuated parasites (GAPs) do not require attenuation by irradiation or concomitant drug treatment. We previously developed a P. falciparum (Pf) GAP with deletions in P52, P36, and SAP1 genes (PfGAP3KO) and demonstrated its safety and immunogenicity in humans. Here, we further assessed safety, tolerability, and immunogenicity of the PfGAP3KO vaccine and tested its efficacy against controlled human malaria infection (CHMI) in malaria-naïve subjects. The vaccine was delivered by three (n = 6) or five (n = 8) immunizations with ~200 PfGAP3KO-infected mosquito bites per immunization. PfGAP3KO was safe and well tolerated with no breakthrough P. falciparum blood stage infections. Vaccine-related adverse events were predominately localized urticaria related to the numerous mosquito bites administered per vaccination. CHMI via bites with mosquitoes carrying fully infectious Pf NF54 parasites was carried out 1 month after the last immunization. Half of the study participants who received either three or five PfGAP3KO immunizations remained P. falciparum blood stage negative, as shown by a lack of detection of Plasmodium 18S rRNA in the blood for 28 days after CHMI. Six protected study participants received a second CHMI 6 months later, and one remained completely protected. Thus, the PfGAP3KO vaccine was safe and immunogenic and was capable of inducing protection against sporozoite infection. These results warrant further evaluation of PfGAP3KO vaccine efficacy in dose-range finding trials with an injectable formulation.
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Affiliation(s)
- Sean C. Murphy
- Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington; Seattle, WA 98109
- Department of Microbiology, University of Washington; Seattle, WA 98109
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
- Department of Pediatrics, University of Washington; Seattle, WA 98105
| | - James G. Kublin
- Department of Global Health, University of Washington; Seattle, WA 98195
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center; Seattle, WA 98109
| | - Matthew Fishbauger
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Annette M. Seilie
- Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington; Seattle, WA 98109
| | - Kurtis P. Cruz
- Department of Laboratory Medicine and Pathology and Center for Emerging and Re-emerging Infectious Diseases, University of Washington; Seattle, WA 98109
| | - Tracie Mankowski
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Melike Firat
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Sara Magee
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Will Betz
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Heather Kain
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Nelly Camargo
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Meseret T. Haile
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Janna Armstrong
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Emma Fritzen
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Nina Hertoghs
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - D. Noah Sather
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
| | - Leeya F. Pinder
- Department of Obstetrics and Gynecology, University of Washington; Seattle, WA 98195
| | - Gregory A. Deye
- Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health; Bethesda, MD, United States
| | | | - Casey Geber
- The Emmes Company; Rockville, MD, United States
| | | | - Lisa A. Jackson
- Kaiser Permanente Washington Health Research Institute; Seattle, WA
| | - Stefan H.I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute; 307 Westlake Avenue North, Suite 500, Seattle, WA 98109
- Department of Global Health, University of Washington; Seattle, WA 98195
- Department of Pediatrics, University of Washington; Seattle, WA 98105
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Pickford AK, Michel-Todó L, Dupuy F, Mayor A, Alonso PL, Lavazec C, Cortés A. Expression Patterns of Plasmodium falciparum Clonally Variant Genes at the Onset of a Blood Infection in Malaria-Naive Humans. mBio 2021; 12:e0163621. [PMID: 34340541 DOI: 10.1128/mBio.01636-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clonally variant genes (CVGs) play fundamental roles in the adaptation of Plasmodium falciparum to fluctuating conditions of the human host. However, their expression patterns under the natural conditions of the blood circulation have been characterized in detail for only a few specific gene families. Here, we provide a detailed characterization of the complete P. falciparum transcriptome across the full intraerythrocytic development cycle (IDC) at the onset of a blood infection in malaria-naive human volunteers. We found that the vast majority of transcriptional differences between parasites obtained from the volunteers and the parental parasite line maintained in culture occurred in CVGs. In particular, we observed a major increase in the transcript levels of most genes of the pfmc-2tm and gbp families and of specific genes of other families, such as phist, hyp10, rif, or stevor, in addition to previously reported changes in var and clag3 gene expression. Increased transcript levels of individual pfmc-2tm, rif, and stevor genes involved activation in small subsets of parasites. Large transcriptional differences correlated with changes in the distribution of heterochromatin, confirming their epigenetic nature. Furthermore, the similar expression of several CVGs between parasites collected at different time points along the blood infection suggests that the epigenetic memory for multiple CVG families is lost during transmission stages, resulting in a reset of their transcriptional state. Finally, the CVG expression patterns observed in a volunteer likely infected by a single sporozoite suggest that new epigenetic patterns are established during liver stages.
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10
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Moita D, Nunes-Cabaço H, Mendes AM, Prudêncio M. A guide to investigating immune responses elicited by whole-sporozoite pre-erythrocytic vaccines against malaria. FEBS J 2021; 289:3335-3359. [PMID: 33993649 DOI: 10.1111/febs.16016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/19/2021] [Accepted: 05/12/2021] [Indexed: 11/28/2022]
Abstract
In the last few decades, considerable efforts have been made toward the development of efficient vaccines against malaria. Whole-sporozoite (Wsp) vaccines, which induce efficient immune responses against the pre-erythrocytic (PE) stages (sporozoites and liver forms) of Plasmodium parasites, the causative agents of malaria, are among the most promising immunization strategies tested until present. Several Wsp PE vaccination approaches are currently under evaluation in the clinic, including radiation- or genetically-attenuated Plasmodium sporozoites, live parasites combined with chemoprophylaxis, or genetically modified rodent Plasmodium parasites. In addition to the assessment of their protective efficacy, clinical trials of Wsp PE vaccine candidates inevitably involve the thorough investigation of the immune responses elicited by vaccination, as well as the identification of correlates of protection. Here, we review the main methodologies employed to dissect the humoral and cellular immune responses observed in the context of Wsp PE vaccine clinical trials and discuss future strategies to further deepen the knowledge generated by these studies, providing a toolbox for the in-depth analysis of vaccine-induced immunogenicity.
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Affiliation(s)
- Diana Moita
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Helena Nunes-Cabaço
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - António M Mendes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Portugal
| | - Miguel Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Portugal
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11
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Jongo SA, Church LWP, Mtoro AT, Schindler T, Chakravarty S, Ruben AJ, Swanson PA, Kassim KR, Mpina M, Tumbo AM, Milando FA, Qassim M, Juma OA, Bakari BM, Simon B, James ER, Abebe Y, Kc N, Saverino E, Fink M, Cosi G, Gondwe L, Studer F, Styers D, Seder RA, Schindler T, Billingsley PF, Daubenberger C, Sim BKL, Tanner M, Richie TL, Abdulla S, Hoffman SL. Increase of Dose Associated With Decrease in Protection Against Controlled Human Malaria Infection by PfSPZ Vaccine in Tanzanian Adults. Clin Infect Dis 2021; 71:2849-2857. [PMID: 31782768 DOI: 10.1093/cid/ciz1152] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 11/28/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND A vaccine would be an ideal tool for reducing malaria's impact. PfSPZ Vaccine (radiation attenuated, aseptic, purified, cryopreserved Plasmodium falciparum [Pf] sporozoites [SPZ]) has been well tolerated and safe in >1526 malaria-naive and experienced 6-month to 65-year-olds in the United States, Europe, and Africa. When vaccine efficacy (VE) of 5 doses of 2.7 × 105 PfSPZ of PfSPZ Vaccine was assessed in adults against controlled human malaria infection (CHMI) in the United States and Tanzania and intense field transmission of heterogeneous Pf in Mali, Tanzanians had the lowest VE (20%). METHODS To increase VE in Tanzania, we increased PfSPZ/dose (9 × 105 or 1.8 × 106) and decreased numbers of doses to 3 at 8-week intervals in a double blind, placebo-controlled trial. RESULTS All 22 CHMIs in controls resulted in parasitemia by quantitative polymerase chain reaction. For the 9 × 105 PfSPZ group, VE was 100% (5/5) at 3 or 11 weeks (P < .000l, Barnard test, 2-tailed). For 1.8 × 106 PfSPZ, VE was 33% (2/6) at 7.5 weeks (P = .028). VE of dosage groups (100% vs 33%) was significantly different (P = .022). Volunteers underwent repeat CHMI at 37-40 weeks after last dose. 6/6 and 5/6 volunteers developed parasitemia, but time to first parasitemia was significantly longer than controls in the 9 × 105 PfSPZ group (10.89 vs 7.80 days) (P = .039), indicating a significant reduction in parasites in the liver. Antibody and T-cell responses were higher in the 1.8 × 106 PfSPZ group. CONCLUSIONS In Tanzania, increasing the dose from 2.7 × 105 to 9 × 105 PfSPZ increased VE from 20% to 100%, but increasing to 1.8 × 106 PfSPZ significantly reduced VE. CLINICAL TRIALS REGISTRATION NCT02613520.
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Affiliation(s)
- Said A Jongo
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
| | | | - Ali T Mtoro
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
| | - Tobias Schindler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | | | | | - Phillip A Swanson
- Vaccine Research Center (VRC), National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Kamaka R Kassim
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
| | - Maximillian Mpina
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - Anneth-Mwasi Tumbo
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - Florence A Milando
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
| | - Munira Qassim
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
| | - Omar A Juma
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
| | - Bakari M Bakari
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
| | - Beatus Simon
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
| | | | | | | | | | - Martina Fink
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - Glenda Cosi
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - Linda Gondwe
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - Fabian Studer
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | | | - Robert A Seder
- Vaccine Research Center (VRC), National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Tobias Schindler
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | | | - Claudia Daubenberger
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | - B Kim Lee Sim
- Sanaria Inc., Rockville, Maryland, USA.,Protein Potential LLC, Rockville, Maryland, USA
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Switzerland
| | | | - Salim Abdulla
- Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania
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12
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Lamsfus Calle C, Fendel R, Singh A, Richie TL, Hoffman SL, Kremsner PG, Mordmüller B. Expansion of Functional Myeloid-Derived Suppressor Cells in Controlled Human Malaria Infection. Front Immunol 2021; 12:625712. [PMID: 33815377 PMCID: PMC8017236 DOI: 10.3389/fimmu.2021.625712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/22/2021] [Indexed: 12/12/2022] Open
Abstract
Malaria can cause life-threatening complications which are often associated with inflammatory reactions. More subtle, but also contributing to the burden of disease are chronic, often subclinical infections, which result in conditions like anemia and immunologic hyporesponsiveness. Although very frequent, such infections are difficult to study in endemic regions because of interaction with concurrent infections and immune responses. In particular, knowledge about mechanisms of malaria-induced immunosuppression is scarce. We measured circulating immune cells by cytometry in healthy, malaria-naïve, adult volunteers undergoing controlled human malaria infection (CHMI) with a focus on potentially immunosuppressive cells. Infectious Plasmodium falciparum (Pf) sporozoites (SPZ) (PfSPZ Challenge) were inoculated during two independent studies to assess malaria vaccine efficacy. Volunteers were followed daily until parasites were detected in the circulation by RT-qPCR. This allowed us to analyze immune responses during pre-patency and at very low parasite densities in malaria-naïve healthy adults. We observed a consistent increase in circulating polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) in volunteers who developed P. falciparum blood stage parasitemia. The increase was independent of preceding vaccination with a pre-erythrocytic malaria vaccine. PMN-MDSC were functional, they suppressed CD4+ and CD8+ T cell proliferation as shown by ex-vivo co-cultivation with stimulated T cells. PMN-MDSC reduced T cell proliferation upon stimulation by about 50%. Interestingly, high circulating PMN-MDSC numbers were associated with lymphocytopenia. The number of circulating regulatory T cells (Treg) and monocytic MDSC (M-MDSC) showed no significant parasitemia-dependent variation. These results highlight PMN-MDSC in the peripheral circulation as an early indicator of infection during malaria. They suppress CD4+ and CD8+ T cell proliferation in vitro. Their contribution to immunosuppression in vivo in subclinical and uncomplicated malaria will be the subject of further research. Pre-emptive antimalarial pre-treatment of vaccinees to reverse malaria-associated PMN-MDSC immunosuppression could improve vaccine response in exposed individuals.
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Affiliation(s)
| | - Rolf Fendel
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Anurag Singh
- Department of Pediatrics 1, University Children's Hospital Tübingen, Tübingen, Germany.,Institute for Clinical and Experimental Transfusion Medicine, University Hospital Tübingen, Tübingen, Germany
| | | | | | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
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13
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Wattanakul T, Baker M, Mohrle J, McWhinney B, Hoglund RM, McCarthy JS, Tarning J. Semimechanistic Pharmacokinetic and Pharmacodynamic Modeling of Piperaquine in a Volunteer Infection Study with Plasmodium falciparum Blood-Stage Malaria. Antimicrob Agents Chemother 2021; 65:e01583-20. [PMID: 33468477 DOI: 10.1128/AAC.01583-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/10/2021] [Indexed: 11/20/2022] Open
Abstract
Dihydroartemisinin-piperaquine is a recommended first-line artemisinin combination therapy for Plasmodium falciparum malaria. Piperaquine is also under consideration for other antimalarial combination therapies. The aim of this study was to develop a pharmacokinetic-pharmacodynamic model that might be useful when optimizing the use of piperaquine in new antimalarial combination therapies. The pharmacokinetic-pharmacodynamic model was developed using data from a previously reported dose-ranging study where 24 healthy volunteers were inoculated with 1,800 blood-stage Plasmodium falciparum parasites. All volunteers received a single oral dose of piperaquine (960 mg, 640 mg, or 480 mg) on day 7 or day 8 after parasite inoculation in separate cohorts. Parasite densities were measured by quantitative PCR (qPCR), and piperaquine levels were measured in plasma samples. We used nonlinear mixed-effect modeling to characterize the pharmacokinetic properties of piperaquine and the parasite dynamics associated with piperaquine exposure. The pharmacokinetics of piperaquine was described by a three-compartment disposition model. A semimechanistic parasite dynamics model was developed to explain the maturation of parasites, sequestration of mature parasites, synchronicity of infections, and multiplication of parasites, as seen in natural clinical infections with P. falciparum malaria. Piperaquine-associated parasite killing was estimated using a maximum effect (E max) function. Treatment simulations (i.e., 3-day oral dosing of dihydroartemisinin-piperaquine) indicated that to be able to combat multidrug-resistant infections, an ideal additional drug in a new antimalarial triple-combination therapy should have a parasite reduction ratio of ≥102 per life cycle (38.8 h) with a duration of action of ≥2 weeks. The semimechanistic pharmacokinetic-pharmacodynamic model described here offers the potential to be a valuable tool for assessing and optimizing current and new antimalarial drug combination therapies containing piperaquine and the impact of these therapies on killing multidrug-resistant infections. (This study has been registered in the Australian and New Zealand Clinical Trials Registry under no. ANZCTRN12613000565741.).
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14
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Moon JE, Ockenhouse C, Regules JA, Vekemans J, Lee C, Chuang I, Traskine M, Jongert E, Ivinson K, Morelle D, Komisar JL, Lievens M, Sedegah M, Garver LS, Sikaffy AK, Waters NC, Ballou WR, Ofori-Anyinam O. A Phase IIa Controlled Human Malaria Infection and Immunogenicity Study of RTS,S/AS01E and RTS,S/AS01B Delayed Fractional Dose Regimens in Malaria-Naive Adults. J Infect Dis 2021; 222:1681-1691. [PMID: 32687161 PMCID: PMC7552430 DOI: 10.1093/infdis/jiaa421] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 07/17/2020] [Indexed: 01/04/2023] Open
Abstract
Background A previous RTS,S/AS01B vaccine challenge trial demonstrated that a 3-dose (0-1-7–month) regimen with a fractional third dose can produce high vaccine efficacy (VE) in adults challenged 3 weeks after vaccination. This study explored the VE of different delayed fractional dose regimens of adult and pediatric RTS,S/AS01 formulations. Methods A total of 130 participants were randomized into 5 groups. Four groups received 3 doses of RTS,S/AS01B or RTS,S/AS01E on a 0-1-7–month schedule, with the final 1 or 2 doses being fractional (one-fifth dose volume). One group received 1 full (month 0) and 1 fractional (month 7) dose of RTS,S/AS01E. Immunized and unvaccinated control participants underwent Plasmodium falciparum–infected mosquito challenge (controlled human malaria infection) 3 months after immunization, a timing chosen to potentially discriminate VEs between groups. Results The VE of 3-dose formulations ranged from 55% (95% confidence interval, 27%–72%) to 76% (48%–89%). Groups administered equivalent formulations of RTS,S/AS01E and RTS,S/AS01B demonstrated comparable VE. The 2-dose group demonstrated lower VE (29% [95% confidence interval, 6%–46%]). All regimens were well tolerated and immunogenic, with trends toward higher anti-circumsporozoite antibody titers in participants protected against infection. Conclusions RTS,S/AS01E can provide VE comparable to an equivalent RTS,S/AS01B regimen in adults, suggesting a universal formulation may be considered. Results also suggest that the 2-dose regimen is inferior to the 3-dose regimens evaluated. Clinical Trial Registration NCT03162614
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Affiliation(s)
- James E Moon
- Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | | | - Jason A Regules
- Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | | | - Cynthia Lee
- PATH-Malaria Vaccine Initiative, Washington, DC, USA
| | - Ilin Chuang
- Naval Medical Research Center, Silver Spring, Maryland, USA
| | | | | | - Karen Ivinson
- PATH-Malaria Vaccine Initiative, Washington, DC, USA
| | | | - Jack L Komisar
- Naval Medical Research Center, Silver Spring, Maryland, USA
| | | | - Martha Sedegah
- Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Lindsey S Garver
- Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - April K Sikaffy
- Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Norman C Waters
- Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
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15
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Dejon-Agobe JC, Ateba-Ngoa U, Lalremruata A, Homoet A, Engelhorn J, Nouatin OP, Edoa JR, Fernandes JF, Esen M, Mouwenda YD, Betouke Ongwe EM, Massinga-Loembe M, Hoffman SL, Sim BKL, Theisen M, Kremsner PG, Adegnika AA, Lell B, Mordmüller B. Controlled Human Malaria Infection of Healthy Adults With Lifelong Malaria Exposure to Assess Safety, Immunogenicity, and Efficacy of the Asexual Blood Stage Malaria Vaccine Candidate GMZ2. Clin Infect Dis 2020; 69:1377-1384. [PMID: 30561539 DOI: 10.1093/cid/ciy1087] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/18/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND GMZ2 is a recombinant malaria vaccine inducing immune responses against Plasmodium falciparum (Pf) merozoite surface protein-3 and glutamate-rich protein. We used standardized controlled human malaria infection (CHMI) to assess the efficacy of this asexual blood-stage vaccine. METHODS We vaccinated 50 healthy, adult volunteers with lifelong exposure to Pf 3 times, at 4-week intervals, with 30 or 100 µg GMZ2 formulated in CAF01, a liposome-based adjuvant; 100 µg GMZ2, formulated in Alhydrogel; or a control vaccine (Verorab). Approximately 13 weeks after the last vaccination, 35/50 volunteers underwent CHMI by direct venous inoculation of 3200 Pf sporozoites (Sanaria® PfSPZ Challenge). RESULTS Adverse events were similarly distributed between GMZ2 and control vaccinees. Baseline-corrected anti-GMZ2 antibody concentrations 4 weeks after the last vaccination were higher in all 3 GMZ2-vaccinated arms, compared to the control group. All GMZ2 formulations induced similar antibody levels. CHMI resulted in 29/34 (85%) volunteers with Pf parasitemia and 15/34 (44%) with malaria (parasitemia and symptoms). The proportion of participants with malaria (2/5 control, 6/10 GMZ2-Alhydrogel, 2/8 30 µg GMZ2-CAF01, and 5/11 100 µg GMZ2-CAF01) and the time it took them to develop malaria were similar in all groups. Baseline, vaccine-specific antibody concentrations were associated with protection against malaria. CONCLUSIONS GMZ2 is well tolerated and immunogenic in lifelong-Pf-exposed adults from Gabon, with similar antibody responses regardless of formulation. CHMI showed no protective effect of prior vaccination with GMZ2, although baseline, vaccine-specific antibody concentrations were associated with protection. CHMI with the PfSPZ Challenge is a potent new tool to validate asexual, blood-stage malaria vaccines in Africa. CLINICAL TRIALS REGISTRATION Pan-African Clinical Trials: PACTR201503001038304.
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Affiliation(s)
- Jean Claude Dejon-Agobe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Ulysse Ateba-Ngoa
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany.,Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Albert Lalremruata
- Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Andreas Homoet
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Julie Engelhorn
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Odilon Paterne Nouatin
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Jean Ronald Edoa
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - José F Fernandes
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Meral Esen
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Yoanne Darelle Mouwenda
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Eunice M Betouke Ongwe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon
| | - Marguerite Massinga-Loembe
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | | | | | - Michael Theisen
- Department for Congenital Disorders, Statens Serum Institut, Denmark.,Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Denmark.,Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Peter G Kremsner
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Ayôla A Adegnika
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany.,Department of Parasitology, Leiden University Medical Center, The Netherlands
| | - Bertrand Lell
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
| | - Benjamin Mordmüller
- Centre de Recherches Médicales de Lambaréné and African Partner Institution, German Center for Infection Research, Gabon.,Institut für Tropenmedizin, Universität Tübingen and German Center for Infection Research, Germany
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16
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Camponovo F, Campo JJ, Le TQ, Oberai A, Hung C, Pablo JV, Teng AA, Liang X, Sim BKL, Jongo S, Abdulla S, Tanner M, Hoffman SL, Daubenberger C, Penny MA. Proteome-wide analysis of a malaria vaccine study reveals personalized humoral immune profiles in Tanzanian adults. eLife 2020; 9:53080. [PMID: 32662772 PMCID: PMC7386907 DOI: 10.7554/elife.53080] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 07/10/2020] [Indexed: 12/31/2022] Open
Abstract
Tanzanian adult male volunteers were immunized by direct venous inoculation with radiation-attenuated, aseptic, purified, cryopreserved Plasmodium falciparum (Pf) sporozoites (PfSPZ Vaccine) and protective efficacy assessed by homologous controlled human malaria infection (CHMI). Serum immunoglobulin G (IgG) responses were analyzed longitudinally using a Pf protein microarray covering 91% of the proteome, providing first insights into naturally acquired and PfSPZ Vaccine-induced whole parasite antibody profiles in malaria pre-exposed Africans. Immunoreactivity was identified against 2239 functionally diverse Pf proteins, showing a wide breadth of humoral response. Antibody-based immune ‘fingerprints’ in these individuals indicated a strong person-specific immune response at baseline, with little changes in the overall humoral immunoreactivity pattern measured after immunization. The moderate increase in immunogenicity following immunization and the extensive and variable breadth of humoral immune response observed in the volunteers at baseline suggest that pre-exposure reduces vaccine-induced antigen reactivity in unanticipated ways.
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Affiliation(s)
- Flavia Camponovo
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | | | - Amit Oberai
- Antigen Discovery Inc, Irvine, United States
| | | | | | - Andy A Teng
- Antigen Discovery Inc, Irvine, United States
| | | | | | - Said Jongo
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Salim Abdulla
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | - Claudia Daubenberger
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Melissa A Penny
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
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17
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Achan J, Reuling IJ, Yap XZ, Dabira E, Ahmad A, Cox M, Nwakanma D, Tetteh K, Wu L, Bastiaens GJH, Abebe Y, Manoj A, Kaur H, Miura K, Long C, Billingsley PF, Sim BKL, Hoffman SL, Drakeley C, Bousema T, D’Alessandro U. Serologic Markers of Previous Malaria Exposure and Functional Antibodies Inhibiting Parasite Growth Are Associated With Parasite Kinetics Following a Plasmodium falciparum Controlled Human Infection. Clin Infect Dis 2020; 70:2544-2552. [PMID: 31402382 PMCID: PMC7286377 DOI: 10.1093/cid/ciz740] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 08/01/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND We assessed the impact of exposure to Plasmodium falciparum on parasite kinetics, clinical symptoms, and functional immunity after controlled human malaria infection (CHMI) in 2 cohorts with different levels of previous malarial exposure. METHODS Nine adult males with high (sero-high) and 10 with low (sero-low) previous exposure received 3200 P. falciparum sporozoites (PfSPZ) of PfSPZ Challenge by direct venous inoculation and were followed for 35 days for parasitemia by thick blood smear (TBS) and quantitative polymerase chain reaction. Endpoints were time to parasitemia, adverse events, and immune responses. RESULTS Ten of 10 (100%) volunteers in the sero-low and 7 of 9 (77.8%) in the sero-high group developed parasitemia detected by TBS in the first 28 days (P = .125). The median time to parasitemia was significantly shorter in the sero-low group than the sero-high group (9 days [interquartile range {IQR} 7.5-11.0] vs 11.0 days [IQR 7.5-18.0], respectively; log-rank test, P = .005). Antibody recognition of sporozoites was significantly higher in the sero-high (median, 17.93 [IQR 12.95-24] arbitrary units [AU]) than the sero-low volunteers (median, 10.54 [IQR, 8.36-12.12] AU) (P = .006). Growth inhibitory activity was significantly higher in the sero-high (median, 21.8% [IQR, 8.15%-29.65%]) than in the sero-low group (median, 8.3% [IQR, 5.6%-10.23%]) (P = .025). CONCLUSIONS CHMI was safe and well tolerated in this population. Individuals with serological evidence of higher malaria exposure were able to better control infection and had higher parasite growth inhibitory activity. CLINICAL TRIALS REGISTRATION NCT03496454.
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Affiliation(s)
- Jane Achan
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Isaie J Reuling
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Xi Zen Yap
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Edgard Dabira
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Abdullahi Ahmad
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Momodou Cox
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Davis Nwakanma
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Kevin Tetteh
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Lindsey Wu
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Guido J H Bastiaens
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | | | - Harparkash Kaur
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Carole Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | | | | | | | - Chris Drakeley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Umberto D’Alessandro
- Disease Control and Elimination Theme, Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, The Gambia
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18
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Laurens MB, Berry AA, Travassos MA, Strauss K, Adams M, Shrestha B, Li T, Eappen A, Manoj A, Abebe Y, Murshedkar T, Gunasekera A, Richie TL, Lyke KE, Plowe CV, Kennedy JK, Potter GE, Deye GA, Sim BKL, Hoffman SL. Dose-Dependent Infectivity of Aseptic, Purified, Cryopreserved Plasmodium falciparum 7G8 Sporozoites in Malaria-Naive Adults. J Infect Dis 2020; 220:1962-1966. [PMID: 31419294 DOI: 10.1093/infdis/jiz410] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 08/13/2019] [Indexed: 12/11/2022] Open
Abstract
Direct venous inoculation of 3.2 × 103 aseptic, purified, cryopreserved, vialed Plasmodium falciparum (Pf) strain NF54 sporozoites, PfSPZ Challenge (NF54), has been used for controlled human malaria infection (CHMI) in the United States, 4 European countries, and 6 African countries. In nonimmune adults, this results in 100% infection rates. We conducted a double-blind, randomized, dose-escalation study to assess the infectivity of the 7G8 clone of Pf (PfSPZ Challenge [7G8]). Results showed dose-dependent infectivity from 43% for 8 × 102 PfSPZ to 100% for 4.8 × 103 PfSPZ. PfSPZ Challenge (7G8) will allow for more complete assessment by CHMI of antimalarial vaccines and drugs.
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Affiliation(s)
- Matthew B Laurens
- Malaria Research Group, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | - Andrea A Berry
- Malaria Research Group, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | - Mark A Travassos
- Malaria Research Group, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | - Kathy Strauss
- Malaria Research Group, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | - Matthew Adams
- Malaria Research Group, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | - Biraj Shrestha
- Malaria Research Group, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | - Tao Li
- Sanaria, Inc, Rockville, Maryland
| | | | | | | | | | | | | | - Kirsten E Lyke
- Malaria Research Group, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore
| | | | | | | | - Gregory A Deye
- Parasitology and International Programs Branch, Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
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19
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Metzger WG, Theurer A, Pfleiderer A, Molnar Z, Maihöfer-Braatting D, Bissinger AL, Sulyok Z, Köhler C, Egger-Adam D, Lalremruata A, Esen M, Lee Sim K, Hoffman S, Rabinovich R, Chaccour C, Alonso P, Mordmüller BG, Kremsner PG. Ivermectin for causal malaria prophylaxis: a randomised controlled human infection trial. Trop Med Int Health 2020; 25:380-386. [PMID: 31808594 DOI: 10.1111/tmi.13357] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Ivermectin is safe and widely used for treating helminth infections. It also kills arthropods feeding on treated subjects, including malaria vectors. Thus, ivermectin mass drug administration as an additional tool for malaria control is being evaluated by WHO. As in vitro data, animal experiments and epidemiological observations suggest that ivermectin has a direct effect on the liver stages of the malaria parasite, this study was designed to assess the prophylactic effect of ivermectin on Plasmodium falciparum controlled human malaria infection. METHODS A total of 4 volunteers were randomised to placebo, and 8 volunteers were randomised to receive ivermectin 0.4 mg/kg, orally, once 2 h before being experimentally infected intravenously with 3200 P. falciparum sporozoites. The primary endpoint was time to parasitaemia detected by positive thick blood smear; RT-qPCR was performed in parallel. RESULTS All but one volunteer became thick blood smear positive between day 11 and day 12 after infection, and there was no significant effect of ivermectin on parasitaemia. CONCLUSION Ivermectin - at the dose used - has no clinically relevant activity against the pre-erythrocytic stages of P. falciparum.
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Affiliation(s)
- Wolfram G Metzger
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | - Antje Theurer
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | - Anne Pfleiderer
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | - Zsofia Molnar
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | | | - Alfred L Bissinger
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | - Zita Sulyok
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | - Carsten Köhler
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | - Diane Egger-Adam
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | - Albert Lalremruata
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | - Meral Esen
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany
| | | | | | | | | | | | - Benjamin G Mordmüller
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Peter G Kremsner
- Institute for Tropical Medicine, German Center for Infection Research, Tübingen, Germany.,Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
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20
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McCarthy JS, Rückle T, Elliott SL, Ballard E, Collins KA, Marquart L, Griffin P, Chalon S, Möhrle JJ. A Single-Dose Combination Study with the Experimental Antimalarials Artefenomel and DSM265 To Determine Safety and Antimalarial Activity against Blood-Stage Plasmodium falciparum in Healthy Volunteers. Antimicrob Agents Chemother 2019; 64:e01371-19. [PMID: 31685476 DOI: 10.1128/AAC.01371-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 11/01/2019] [Indexed: 12/12/2022] Open
Abstract
Artefenomel and DSM265 are two new compounds that have been shown to be well tolerated and effective when administered as monotherapy malaria treatment. This study aimed to determine the safety, pharmacokinetics, and pharmacodynamics of artefenomel and DSM265 administered in combination to healthy subjects in a volunteer infection study using the Plasmodium falciparum-induced blood-stage malaria model. Thirteen subjects were inoculated with parasite-infected erythrocytes on day 0 and received a single oral dose of artefenomel and DSM265 on day 7. Cohort 1 (n = 8) received 200 mg artefenomel plus 100 mg DSM265, and cohort 2 (n = 5) received 200 mg artefenomel plus 50 mg DSM265. Blood samples were collected to measure parasitemia, gametocytemia, and artefenomel-DSM265 plasma concentrations. There were no treatment-related adverse events. The pharmacokinetic profiles of artefenomel and DSM265 were similar to those of the compounds when administered as monotherapy, suggesting no pharmacokinetic interactions. A reduction in parasitemia occurred in all subjects following treatment (log10 parasite reduction ratios over 48 h [PRR48] of 2.80 for cohort 1 and 2.71 for cohort 2; parasite clearance half-lives of 5.17 h for cohort 1 and 5.33 h for cohort 2). Recrudescence occurred in 5/8 subjects in cohort 1 between days 19 and 28 and in 5/5 subjects in cohort 2 between days 15 and 22. Low-level gametocytemia (1 to 330 female gametocytes/ml) was detected in all subjects from day 14. The results of this single-dosing combination study support the further clinical development of the use of artefenomel and DSM265 in combination as a treatment for falciparum malaria. (This study has been registered at ClinicalTrials.gov under identifier NCT02389348.).
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21
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Walk J, Sauerwein RW. Activatory Receptor NKp30 Predicts NK Cell Activation During Controlled Human Malaria Infection. Front Immunol 2019; 10:2864. [PMID: 31921133 PMCID: PMC6916516 DOI: 10.3389/fimmu.2019.02864] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 11/21/2019] [Indexed: 12/12/2022] Open
Abstract
Natural killer (NK) cells are known to be activated during malaria infection, exhibiting both cytokine production and cytotoxic functions. However, NK cells are heterogeneous in their expression of surface activatory and inhibitory receptors which may influence their response to malaria parasites. Here, we studied the surface marker profile and activation dynamics of NK cells during a Controlled Human Malaria Infection in 12 healthy volunteers. Although there was significant inter-patient variability in timing and magnitude of NK cell activation, we found a consistent and strong increase in expression of the activatory receptor NKp30. Moreover, high baseline NKp30 expression was associated with NK cell activation at lower parasite densities. Our data suggest that NKp30 expression may influence the NK cell response to P. falciparum, explaining inter-patient heterogeneity and suggesting a functional role for this receptor in malaria.
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Affiliation(s)
- Jona Walk
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Robert W Sauerwein
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
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22
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Kapulu MC, Njuguna P, Hamaluba MM. Controlled Human Malaria Infection in Semi-Immune Kenyan Adults (CHMI-SIKA): a study protocol to investigate in vivo Plasmodium falciparum malaria parasite growth in the context of pre-existing immunity. Wellcome Open Res 2019; 3:155. [PMID: 31803847 PMCID: PMC6871356 DOI: 10.12688/wellcomeopenres.14909.2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2019] [Indexed: 01/09/2023] Open
Abstract
Malaria remains a major public health burden despite approval for implementation of a partially effective pre-erythrocytic malaria vaccine. There is an urgent need to accelerate development of a more effective multi-stage vaccine. Adults in malaria endemic areas may have substantial immunity provided by responses to the blood stages of malaria parasites, but field trials conducted on several blood-stage vaccines have not shown high levels of efficacy. We will use the controlled human malaria infection (CHMI) models with malaria-exposed volunteers to identify correlations between immune responses and parasite growth rates in vivo. Immune responses more strongly associated with control of parasite growth should be prioritized to accelerate malaria vaccine development. We aim to recruit up to 200 healthy adult volunteers from areas of differing malaria transmission in Kenya, and after confirming their health status through clinical examination and routine haematology and biochemistry, we will comprehensively characterize immunity to malaria using >100 blood-stage antigens. We will administer 3,200 aseptic, purified, cryopreserved Plasmodium falciparum sporozoites (PfSPZ Challenge) by direct venous inoculation. Serial quantitative polymerase chain reaction to measure parasite growth rate in vivo will be undertaken. Clinical and laboratory monitoring will be undertaken to ensure volunteer safety. In addition, we will also explore the perceptions and experiences of volunteers and other stakeholders in participating in a malaria volunteer infection study. Serum, plasma, peripheral blood mononuclear cells and whole blood will be stored to allow a comprehensive assessment of adaptive and innate host immunity. We will use CHMI in semi-immune adult volunteers to relate parasite growth outcomes with antibody responses and other markers of host immunity. Registration: ClinicalTrials.gov identifier NCT02739763.
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Affiliation(s)
- Melissa C. Kapulu
- KEMRI-Wellcome Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University Oxford, Oxford, UK
| | | | | | - CHMI-SIKA Study Team
- KEMRI-Wellcome Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University Oxford, Oxford, UK
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23
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Kapulu MC, Njuguna P, Hamaluba MM. Controlled Human Malaria Infection in Semi-Immune Kenyan Adults (CHMI-SIKA): a study protocol to investigate in vivo Plasmodium falciparum malaria parasite growth in the context of pre-existing immunity. Wellcome Open Res 2018; 3:155. [PMID: 31803847 PMCID: PMC6871356 DOI: 10.12688/wellcomeopenres.14909.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2018] [Indexed: 10/20/2023] Open
Abstract
Malaria remains a major public health burden despite approval for implementation of a partially effective pre-erythrocytic malaria vaccine. There is an urgent need to accelerate development of a more effective multi-stage vaccine. Adults in malaria endemic areas may have substantial immunity provided by responses to the blood stages of malaria parasites, but field trials conducted on several blood-stage vaccines have not shown high levels of efficacy. We will use controlled human malaria infection (CHMI) studies with malaria-exposed volunteers to identify correlations between immune responses and parasite growth rates in vivo. Immune responses more strongly associated with control of parasite growth should be prioritized to accelerate malaria vaccine development. We aim to recruit up to 200 healthy adult volunteers from areas of differing malaria transmission in Kenya, and after confirming their health status through clinical examination and routine haematology and biochemistry, we will comprehensively characterize immunity to malaria using >100 blood-stage antigens. We will administer 3,200 aseptic, purified, cryopreserved Plasmodium falciparum sporozoites (PfSPZ Challenge) by direct venous inoculation. Serial quantitative polymerase chain reaction to measure parasite growth rate in vivo will be undertaken. Clinical and laboratory monitoring will be undertaken to ensure volunteer safety. In addition, we will also explore the perceptions and experiences of volunteers and other stakeholders in participating in a malaria volunteer infection study. Serum, plasma, peripheral blood mononuclear cells and extracted DNA will be stored to allow a comprehensive assessment of adaptive and innate host immunity. We will use CHMI in semi-immune adult volunteers to relate parasite growth outcomes with antibody responses and other markers of host immunity. Registration: ClinicalTrials.gov identifier NCT02739763.
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Affiliation(s)
- Melissa C. Kapulu
- KEMRI-Wellcome Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University Oxford, Oxford, UK
| | | | | | - CHMI-SIKA Study Team
- KEMRI-Wellcome Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University Oxford, Oxford, UK
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24
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Behet MC, Kurtovic L, van Gemert GJ, Haukes CM, Siebelink-Stoter R, Graumans W, van de Vegte-Bolmer MG, Scholzen A, Langereis JD, Diavatopoulos DA, Beeson JG, Sauerwein RW. The Complement System Contributes to Functional Antibody-Mediated Responses Induced by Immunization with Plasmodium falciparum Malaria Sporozoites. Infect Immun 2018; 86:e00920-17. [PMID: 29735521 PMCID: PMC6013677 DOI: 10.1128/iai.00920-17] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/16/2018] [Indexed: 11/20/2022] Open
Abstract
Long-lasting and sterile homologous protection against malaria can be achieved by the exposure of malaria-naive volunteers under chemoprophylaxis to Plasmodium falciparum-infected mosquitoes (chemoprophylaxis and sporozoite [CPS] immunization). While CPS-induced antibodies neutralize sporozoite infectivity in vitro and in vivo, antibody-mediated effector mechanisms are still poorly understood. Here, we investigated whether complement contributes to CPS-induced preerythrocytic immunity. Sera collected before and after CPS immunization in the presence of active or inactive complement were assessed for the recognition of homologous NF54 and heterologous NF135.C10 sporozoites, complement fixation, sporozoite lysis, and possible subsequent effects on in vitro sporozoite infectivity in human hepatocytes. CPS immunization induced sporozoite-specific IgM (P < 0.0001) and IgG (P = 0.001) antibodies with complement-fixing capacities (P < 0.0001). Sporozoite lysis (P = 0.017), traversal (P < 0.0001), and hepatocyte invasion inhibition (P < 0.0001) by CPS-induced antibodies were strongly enhanced in the presence of active complement. Complement-mediated invasion inhibition in the presence of CPS-induced antibodies negatively correlated with cumulative parasitemia during CPS immunizations (P = 0.013). While IgG antibodies similarly recognized homologous and heterologous sporozoites, IgM binding to heterologous sporozoites was reduced (P = 0.023). Although CPS-induced antibodies did not differ in their abilities to fix complement, lyse sporozoites, or inhibit the traversal of homologous and heterologous sporozoites, heterologous sporozoite invasion was more strongly inhibited in the presence of active complement (P = 0.008). These findings demonstrate that CPS-induced antibodies have complement-fixing activity, thereby significantly further enhancing the functional inhibition of homologous and heterologous sporozoite infectivity in vitro The combined data highlight the importance of complement as an additional immune effector mechanism in preerythrocytic immunity after whole-parasite immunization against Plasmodium falciparum malaria.
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Affiliation(s)
- Marije C Behet
- Radboud University Medical Center, Department of Medical Microbiology, Nijmegen, The Netherlands
| | - Liriye Kurtovic
- Burnet Institute, Melbourne, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Geert-Jan van Gemert
- Radboud University Medical Center, Department of Medical Microbiology, Nijmegen, The Netherlands
| | - Celine M Haukes
- Radboud University Medical Center, Department of Medical Microbiology, Nijmegen, The Netherlands
| | - Rianne Siebelink-Stoter
- Radboud University Medical Center, Department of Medical Microbiology, Nijmegen, The Netherlands
| | - Wouter Graumans
- Radboud University Medical Center, Department of Medical Microbiology, Nijmegen, The Netherlands
| | | | - Anja Scholzen
- Radboud University Medical Center, Department of Medical Microbiology, Nijmegen, The Netherlands
| | - Jeroen D Langereis
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center and Radboud Center for Infectious Diseases, Nijmegen, The Netherlands
| | - Dimitri A Diavatopoulos
- Laboratory of Pediatric Infectious Diseases, Radboud University Medical Center and Radboud Center for Infectious Diseases, Nijmegen, The Netherlands
| | - James G Beeson
- Burnet Institute, Melbourne, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Australia
- Department of Medical Microbiology, Monash University, Clayton, Australia
| | - Robert W Sauerwein
- Radboud University Medical Center, Department of Medical Microbiology, Nijmegen, The Netherlands
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25
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Abstract
Controlled human malaria infection (CHMI) entails deliberate infection with malaria parasites either by mosquito bite or by direct injection of sporozoites or parasitized erythrocytes. When required, the resulting blood-stage infection is curtailed by the administration of antimalarial drugs. Inducing a malaria infection via inoculation with infected blood was first used as a treatment (malariotherapy) for neurosyphilis in Europe and the United States in the early 1900s. More recently, CHMI has been applied to the fields of malaria vaccine and drug development, where it is used to evaluate products in well-controlled early-phase proof-of-concept clinical studies, thus facilitating progression of only the most promising candidates for further evaluation in areas where malaria is endemic. Controlled infections have also been used to immunize against malaria infection. Historically, CHMI studies have been restricted by the need for access to insectaries housing infected mosquitoes or suitable malaria-infected individuals. Evaluation of vaccine and drug candidates has been constrained in these studies by the availability of a limited number of Plasmodium falciparum isolates. Recent advances have included cryopreservation of sporozoites, the manufacture of well-characterized and genetically distinct cultured malaria cell banks for blood-stage infection, and the availability of Plasmodium vivax-specific reagents. These advances will help to accelerate malaria vaccine and drug development by making the reagents for CHMI more widely accessible and also enabling a more rigorous evaluation with multiple parasite strains and species. Here we discuss the different applications of CHMI, recent advances in the use of CHMI, and ongoing challenges for consideration.
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26
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Abstract
Malaria is a critical public health problem resulting in substantial morbidity and
mortality, particularly in developing countries. Owing to the development of resistance
toward current therapies, novel approaches to accelerate the development efforts of new
malaria therapeutics are urgently needed. There have been significant advancements in the
development of in vitro and in vivo experiments that generate data used to inform
decisions about the potential merit of new compounds. A comprehensive disease-drug model
capable of integrating discrete data from different preclinical and clinical components
would be a valuable tool across all stages of drug development. This could have an
enormous impact on the otherwise slow and resource-intensive process of traditional
clinical drug development.
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Affiliation(s)
- Kayla Ann Andrews
- Cognigen Corporation, a subsidiary of Simulations Plus, Buffalo, New York 14221, USA; , , .,Department of Pharmaceutical Sciences, State University of New York, Buffalo, New York 14214, USA
| | - David Wesche
- Bill and Melinda Gates Foundation, Seattle, Washington 98109, USA; ,
| | - James McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Medicine, University of Queensland, Brisbane, Australia;
| | - Jörg J Möhrle
- Medicines for Malaria Venture, Geneva 1215, Switzerland;
| | - Joel Tarning
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, United Kingdom
| | - Luann Phillips
- Cognigen Corporation, a subsidiary of Simulations Plus, Buffalo, New York 14221, USA; , ,
| | - Steven Kern
- Bill and Melinda Gates Foundation, Seattle, Washington 98109, USA; ,
| | - Thaddeus Grasela
- Cognigen Corporation, a subsidiary of Simulations Plus, Buffalo, New York 14221, USA; , ,
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27
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Gómez-Pérez GP, Legarda A, Muñoz J, Sim BKL, Ballester MR, Dobaño C, Moncunill G, Campo JJ, Cisteró P, Jimenez A, Barrios D, Mordmüller B, Pardos J, Navarro M, Zita CJ, Nhamuave CA, García-Basteiro AL, Sanz A, Aldea M, Manoj A, Gunasekera A, Billingsley PF, Aponte JJ, James ER, Guinovart C, Antonijoan RM, Kremsner PG, Hoffman SL, Alonso PL. Controlled human malaria infection by intramuscular and direct venous inoculation of cryopreserved Plasmodium falciparum sporozoites in malaria-naïve volunteers: effect of injection volume and dose on infectivity rates. Malar J 2015; 14:306. [PMID: 26245196 PMCID: PMC4527105 DOI: 10.1186/s12936-015-0817-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 07/22/2015] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Controlled human malaria infection (CHMI) by mosquito bite is a powerful tool for evaluation of vaccines and drugs against Plasmodium falciparum malaria. However, only a small number of research centres have the facilities required to perform such studies. CHMI by needle and syringe could help to accelerate the development of anti-malaria interventions by enabling centres worldwide to employ CHMI. METHODS An open-label CHMI study was performed with aseptic, purified, cryopreserved P. falciparum sporozoites (PfSPZ Challenge) in 36 malaria naïve volunteers. In part A, the effect of the inoculation volume was assessed: 18 participants were injected intramuscularly (IM) with a dose of 2,500 PfSPZ divided into two injections of 10 µL (n = 6), 50 µL (n = 6) or 250 µL (n = 6), respectively. In part B, the injection volume that resulted in highest infectivity rates in part A (10 µL) was used to formulate IM doses of 25,000 PfSPZ (n = 6) and 75,000 PfSPZ (n = 6) divided into two 10-µL injections. Results from a parallel trial led to the decision to add a positive control group (n = 6), each volunteer receiving 3,200 PfSPZ in a single 500-µL injection by direct venous inoculation (DVI). RESULTS Four/six participants in the 10-µL group, 1/6 in the 50-µL group and 2/6 in the 250-µL group developed parasitaemia. Geometric mean (GM) pre-patent periods were 13.9, 14.0 and 15.0 days, respectively. Six/six (100%) participants developed parasitaemia in the 25,000 and 75,000 PfSPZ IM and 3,200 PfSPZ DVI groups. GM pre-patent periods were 12.2, 11.4 and 11.4 days, respectively. Injection of PfSPZ Challenge was well tolerated and safe in all groups. CONCLUSIONS IM injection of 75,000 PfSPZ and DVI injection of 3,200 PfSPZ resulted in infection rates and pre-patent periods comparable to the bite of five PfSPZ-infected mosquitoes. Remarkably, it required 23.4-fold more PfSPZ administered IM than DVI to achieve the same parasite kinetics. These results allow for translation of CHMI from research to routine use, and inoculation of PfSPZ by IM and DVI regimens. TRIAL REGISTRATION ClinicalTrials.gov NCT01771848.
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Affiliation(s)
- Gloria P Gómez-Pérez
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
- Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, PO Box 22660, 1100 DD, Amsterdam, The Netherlands.
| | - Almudena Legarda
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Jose Muñoz
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | | | - María Rosa Ballester
- Drug Research Centre (CIM), Biomedical Research Institute Sant Pau (IIB Sant Pau), Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
- Department of Pharmacology and Therapeutics, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain.
| | - Carlota Dobaño
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Gemma Moncunill
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Joseph J Campo
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
- Antigen Discovery, Inc, Irvine, CA, USA.
| | - Pau Cisteró
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Alfons Jimenez
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Diana Barrios
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Benjamin Mordmüller
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Centre for Infection Research, 72074, Tübingen, Germany.
| | - Josefina Pardos
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Mireia Navarro
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | | | | | - Alberto L García-Basteiro
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.
| | - Ariadna Sanz
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Marta Aldea
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.
| | | | | | | | - John J Aponte
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | | | - Caterina Guinovart
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
| | - Rosa M Antonijoan
- Drug Research Centre (CIM), Biomedical Research Institute Sant Pau (IIB Sant Pau), Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
- Department of Pharmacology and Therapeutics, Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain.
| | - Peter G Kremsner
- Institut für Tropenmedizin, Eberhard Karls Universität Tübingen and German Centre for Infection Research, 72074, Tübingen, Germany.
| | | | - Pedro L Alonso
- ISGlobal, Barcelona Ctr Int Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.
- Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.
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Richie TL, Charoenvit Y, Wang R, Epstein JE, Hedstrom RC, Kumar S, Luke TC, Freilich DA, Aguiar JC, Sacci JB, Sedegah M, Nosek RA, De La Vega P, Berzins MP, Majam VF, Abot EN, Ganeshan H, Richie NO, Banania JG, Baraceros MFB, Geter TG, Mere R, Bebris L, Limbach K, Hickey BW, Lanar DE, Ng J, Shi M, Hobart PM, Norman JA, Soisson LA, Hollingdale MR, Rogers WO, Doolan DL, Hoffman SL. Clinical trial in healthy malaria-naïve adults to evaluate the safety, tolerability, immunogenicity and efficacy of MuStDO5, a five-gene, sporozoite/hepatic stage Plasmodium falciparum DNA vaccine combined with escalating dose human GM-CSF DNA. Hum Vaccin Immunother 2012; 8:1564-84. [PMID: 23151451 PMCID: PMC3601132 DOI: 10.4161/hv.22129] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
When introduced in the 1990s, immunization with DNA plasmids was considered potentially revolutionary for vaccine development, particularly for vaccines intended to induce protective CD8 T cell responses against multiple antigens. We conducted, in 1997−1998, the first clinical trial in healthy humans of a DNA vaccine, a single plasmid encoding Plasmodium falciparum circumsporozoite protein (PfCSP), as an initial step toward developing a multi-antigen malaria vaccine targeting the liver stages of the parasite. As the next step, we conducted in 2000–2001 a clinical trial of a five-plasmid mixture called MuStDO5 encoding pre-erythrocytic antigens PfCSP, PfSSP2/TRAP, PfEXP1, PfLSA1 and PfLSA3. Thirty-two, malaria-naïve, adult volunteers were enrolled sequentially into four cohorts receiving a mixture of 500 μg of each plasmid plus escalating doses (0, 20, 100 or 500 μg) of a sixth plasmid encoding human granulocyte macrophage-colony stimulating factor (hGM-CSF). Three doses of each formulation were administered intramuscularly by needle-less jet injection at 0, 4 and 8 weeks, and each cohort had controlled human malaria infection administered by five mosquito bites 18 d later. The vaccine was safe and well-tolerated, inducing moderate antigen-specific, MHC-restricted T cell interferon-γ responses but no antibodies. Although no volunteers were protected, T cell responses were boosted post malaria challenge. This trial demonstrated the MuStDO5 DNA and hGM-CSF plasmids to be safe and modestly immunogenic for T cell responses. It also laid the foundation for priming with DNA plasmids and boosting with recombinant viruses, an approach known for nearly 15 y to enhance the immunogenicity and protective efficacy of DNA vaccines.
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