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Live attenuated vaccines, a favorable strategy to provide long-term immunity against protozoan diseases. Trends Parasitol 2021; 38:316-334. [PMID: 34896016 DOI: 10.1016/j.pt.2021.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/12/2021] [Accepted: 11/12/2021] [Indexed: 12/25/2022]
Abstract
The control of diseases caused by protozoan parasites is one of the United Nations' Sustainable Development Goals. In recent years much research effort has gone into developing a new generation of live attenuated vaccines (LAVs) against malaria, Chagas disease and leishmaniasis. However, there is a bottleneck related to their biosafety, production, and distribution that slows downs further development. The success of irradiated or genetically attenuated sporozoites against malaria, added to the first LAV against leishmaniasis to be evaluated in clinical trials, is indicative that the drawbacks of LAVs are gradually being overcome. However, whether persistence of LAVs is a prerequisite for sustained long-term immunity remains to be clarified, and the procedures necessary for clinical evaluation of vaccine candidates need to be standardized.
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Alder A, Struck NS, Xu M, Johnson JW, Wang W, Pallant D, Cook MA, Rambow J, Lemcke S, Gilberger TW, Wright GD. A non-reactive natural product precursor of the duocarmycin family has potent and selective antimalarial activity. Cell Chem Biol 2021; 29:840-853.e6. [PMID: 34710358 DOI: 10.1016/j.chembiol.2021.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/15/2021] [Accepted: 10/02/2021] [Indexed: 11/27/2022]
Abstract
We identify a selective nanomolar inhibitor of blood-stage malarial proliferation from a screen of microbial natural product extracts. The responsible compound, PDE-I2, is a precursor of the anticancer duocarmycin family that preserves the class's sequence-specific DNA binding but lacks its signature DNA alkylating cyclopropyl warhead. While less active than duocarmycin, PDE-I2 retains comparable antimalarial potency to chloroquine. Importantly, PDE-I2 is >1,000-fold less toxic to human cell lines than duocarmycin, with mitigated impacts on eukaryotic chromosome stability. PDE-I2 treatment induces severe defects in parasite nuclear segregation leading to impaired daughter cell formation during schizogony. Time-of-addition studies implicate parasite DNA metabolism as the target of PDE-I2, with defects observed in DNA replication and chromosome integrity. We find the effect of duocarmycin and PDE-I2 on parasites is phenotypically indistinguishable, indicating that the DNA binding specificity of duocarmycins is sufficient and the genotoxic cyclopropyl warhead is dispensable for the parasite-specific selectivity of this compound class.
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Affiliation(s)
- Arne Alder
- Centre for Structural Systems Biology, 22607 Hamburg, Germany; Bernhard Nocht Institute for Tropical Medicine, Department of Cellular Parasitology, 20359 Hamburg, Germany; University of Hamburg, Department of Biology, 20146 Hamburg, Germany
| | - Nicole S Struck
- Bernhard Nocht Institute for Tropical Medicine, Department of Cellular Parasitology, 20359 Hamburg, Germany; M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada; German Centre for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Min Xu
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Jarrod W Johnson
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Wenliang Wang
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Daniel Pallant
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Michael A Cook
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Janis Rambow
- Centre for Structural Systems Biology, 22607 Hamburg, Germany; Bernhard Nocht Institute for Tropical Medicine, Department of Cellular Parasitology, 20359 Hamburg, Germany; University of Hamburg, Department of Biology, 20146 Hamburg, Germany
| | - Sarah Lemcke
- Centre for Structural Systems Biology, 22607 Hamburg, Germany; Bernhard Nocht Institute for Tropical Medicine, Department of Cellular Parasitology, 20359 Hamburg, Germany; University of Hamburg, Department of Biology, 20146 Hamburg, Germany
| | - Tim W Gilberger
- Centre for Structural Systems Biology, 22607 Hamburg, Germany; Bernhard Nocht Institute for Tropical Medicine, Department of Cellular Parasitology, 20359 Hamburg, Germany; University of Hamburg, Department of Biology, 20146 Hamburg, Germany.
| | - Gerard D Wright
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada.
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Pre-clinical evaluation of a whole-parasite vaccine to control human babesiosis. Cell Host Microbe 2021; 29:894-903.e5. [PMID: 33989514 DOI: 10.1016/j.chom.2021.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/18/2021] [Accepted: 04/15/2021] [Indexed: 01/31/2023]
Abstract
Babesia spp. are tick-transmitted intra-erythrocytic protozoan parasites that infect humans and animals, causing a flu-like illness and hemolytic anemia. There is currently no human vaccine available. People most at risk of severe disease are the elderly, immunosuppressed, and asplenic individuals. B. microti and B. divergens are the predominant species affecting humans. Here, we present a whole-parasite Babesia vaccine. To establish proof-of-principle, we employed chemically attenuated B. microti parasitized red blood cells from infected mice. To aid clinical translation, we produced liposomes containing killed parasite material. Vaccination significantly reduces peak parasitemia following challenge. B cells and anti-parasite antibodies do not significantly contribute to vaccine efficacy. Protection is abrogated by the removal of CD4+ T cells or macrophages prior to challenge. Importantly, splenectomized mice are protected by vaccination. To further facilitate translation, we prepared a culture-based liposomal vaccine and demonstrate that this performs as a universal vaccine inducing immunity against different human Babesia species.
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Stanisic DI, Fink J, Mayer J, Coghill S, Gore L, Liu XQ, El-Deeb I, Rodriguez IB, Powell J, Willemsen NM, De SL, Ho MF, Hoffman SL, Gerrard J, Good MF. Vaccination with chemically attenuated Plasmodium falciparum asexual blood-stage parasites induces parasite-specific cellular immune responses in malaria-naïve volunteers: a pilot study. BMC Med 2018; 16:184. [PMID: 30293531 PMCID: PMC6174572 DOI: 10.1186/s12916-018-1173-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/11/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The continuing morbidity and mortality associated with infection with malaria parasites highlights the urgent need for a vaccine. The efficacy of sub-unit vaccines tested in clinical trials in malaria-endemic areas has thus far been disappointing, sparking renewed interest in the whole parasite vaccine approach. We previously showed that a chemically attenuated whole parasite asexual blood-stage vaccine induced CD4+ T cell-dependent protection against challenge with homologous and heterologous parasites in rodent models of malaria. METHODS In this current study, we evaluated the immunogenicity and safety of chemically attenuated asexual blood-stage Plasmodium falciparum (Pf) parasites in eight malaria-naïve human volunteers. Study participants received a single dose of 3 × 107 Pf pRBC that had been treated in vitro with the cyclopropylpyrolloindole analogue, tafuramycin-A. RESULTS We demonstrate that Pf asexual blood-stage parasites that are completely attenuated are immunogenic, safe and well tolerated in malaria-naïve volunteers. Following vaccination with a single dose, species and strain transcending Plasmodium-specific T cell responses were induced in recipients. This included induction of Plasmodium-specific lymphoproliferative responses, T cells secreting the parasiticidal cytokines, IFN-γ and TNF, and CD3+CD45RO+ memory T cells. Pf-specific IgG was not detected. CONCLUSIONS This is the first clinical study evaluating a whole parasite blood-stage malaria vaccine. Following administration of a single dose of completely attenuated Pf asexual blood-stage parasites, Plasmodium-specific T cell responses were induced while Pf-specific antibodies were not detected. These results support further evaluation of this chemically attenuated vaccine in humans. TRIAL REGISTRATION Trial registration: ACTRN12614000228684 . Registered 4 March 2014.
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Affiliation(s)
- Danielle I Stanisic
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia.
| | - James Fink
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Johanna Mayer
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Sarah Coghill
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Letitia Gore
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Xue Q Liu
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Ibrahim El-Deeb
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Ingrid B Rodriguez
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Jessica Powell
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Nicole M Willemsen
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Sai Lata De
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | - Mei-Fong Ho
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia
| | | | - John Gerrard
- Gold Coast University Hospital, 1 Hospital Blvd, Southport, Queensland, Australia
| | - Michael F Good
- Institute for Glycomics, Griffith University, Parklands Drive, Southport, Queensland, Australia.
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