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Othman AS, Franke-Fayard BM, Imai T, van der Gracht ETI, Redeker A, Salman AM, Marin-Mogollon C, Ramesar J, Chevalley-Maurel S, Janse CJ, Arens R, Khan SM. OX40 Stimulation Enhances Protective Immune Responses Induced After Vaccination With Attenuated Malaria Parasites. Front Cell Infect Microbiol 2018; 8:247. [PMID: 30073152 PMCID: PMC6060232 DOI: 10.3389/fcimb.2018.00247] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/28/2018] [Indexed: 01/15/2023] Open
Abstract
Protection against a malaria infection can be achieved by immunization with live-attenuated Plasmodium sporozoites and while the precise mechanisms of protection remain unknown, T cell responses are thought to be critical in the elimination of infected liver cells. In cancer immunotherapies, agonistic antibodies that target T cell surface proteins, such as CD27, OX40 (CD134), and 4-1BB (CD137), have been used to enhance T cell function by increasing co-stimulation. In this study, we have analyzed the effect of agonistic OX40 monoclonal antibody treatment on protective immunity induced in mice immunized with genetically attenuated parasites (GAPs). OX40 stimulation enhanced protective immunity after vaccination as shown by an increase in the number of protected mice and delay to blood-stage infection after challenge with wild-type sporozoites. Consistent with the enhanced protective immunity enforced OX40 stimulation resulted in an increased expansion of antigen-experienced effector (CD11ahiCD44hi) CD8+ and CD4+ T cells in the liver and spleen and also increased IFN-γ and TNF producing CD4+ T cells in the liver and spleen. In addition, GAP immunization plus α-OX40 treatment significantly increased sporozoite-specific IgG responses. Thus, we demonstrate that targeting T cell costimulatory receptors can improve sporozoite-based vaccine efficacy.
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Affiliation(s)
- Ahmad Syibli Othman
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands.,Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Terengganu, Malaysia
| | - Blandine M Franke-Fayard
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Takashi Imai
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Esmé T I van der Gracht
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, Netherlands
| | - Anke Redeker
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, Netherlands
| | - Ahmed M Salman
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands.,The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Catherin Marin-Mogollon
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Jai Ramesar
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Chris J Janse
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Ramon Arens
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, Netherlands
| | - Shahid M Khan
- Leiden Malaria Research Group, Parasitology, Leiden University Medical Center, Leiden, Netherlands
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2
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White SE, Harvey SA, Meza G, Llanos A, Guzman M, Gamboa D, Vinetz JM. Acceptability of a herd immunity-focused, transmission-blocking malaria vaccine in malaria-endemic communities in the Peruvian Amazon: an exploratory study. Malar J 2018; 17:179. [PMID: 29703192 PMCID: PMC5921293 DOI: 10.1186/s12936-018-2328-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/18/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND A transmission-blocking vaccine (TBV) to prevent malaria-infected humans from infecting mosquitoes has been increasingly considered as a tool for malaria control and elimination. This study tested the hypothesis that a malaria TBV would be acceptable among residents of a malaria-hypoendemic region. METHODS The study was carried out in six Spanish-speaking rural villages in the Department of Loreto in the Peruvian Amazon. These villages comprise a cohort of 430 households associated with the Peru-Brazil International Centre for Excellence in Malaria Research. Individuals from one-third (143) of enrolled households in an ongoing longitudinal, prospective cohort study in 6 communities in Loreto, Peru, were randomly selected to participate by answering a pre-validated questionnaire. RESULTS All 143 participants expressed desire for a malaria vaccine in general; only 1 (0.7%) expressed unwillingness to receive a transmission-blocking malaria vaccine. Injection was considered most acceptable for adults (97.2%); for children drops in the mouth were preferred (96.8%). Acceptability waned marginally with the prospect of multiple injections (83.8%) and different projected efficacies at 70 and 50% (90.1 and 71.8%, respectively). Respondents demonstrated clear understanding that the vaccine was for community, rather than personal, protection against malaria infection. DISCUSSION In this setting of the Peruvian Amazon, a transmission-blocking malaria vaccine was found to be almost universally acceptable. This study is the first to report that residents of a malaria-endemic region have been queried regarding a malaria vaccine strategy that policy-makers in the industrialized world often dismiss as altruistic.
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Affiliation(s)
- Sara E White
- Division of Infectious Diseases, Department of Medicine, University of California, San Diego School of Medicine, 9500 Gilman Drive 0760, Biomedical Research Facility Room 4A16, La Jolla, CA, 92093-0760, USA
| | - Steven A Harvey
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St. E5030, Baltimore, MD, 21205, USA.
| | - Graciela Meza
- Facultad de Medicina Humana, Universidad Nacional de la Amazonia Peruana, Iquitos, Peru
| | - Alejandro Llanos
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru
| | - Mitchel Guzman
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru
| | - Dionicia Gamboa
- Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru.,Department of Cellular and Molecular Sciences, Faculty of Sciences and Laboratory of Research and Development, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Joseph M Vinetz
- Division of Infectious Diseases, Department of Medicine, University of California, San Diego School of Medicine, 9500 Gilman Drive 0760, Biomedical Research Facility Room 4A16, La Jolla, CA, 92093-0760, USA. .,Malaria and Leishmaniasis Division, Instituto de Medicina Tropical Alexander von Humboldt, Av. Honorio Delgado 430, San Martín de Porres, Lima, Peru. .,Department of Cellular and Molecular Sciences, Faculty of Sciences and Laboratory of Research and Development, Universidad Peruana Cayetano Heredia, Lima, Peru.
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3
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Haeberlein S, Chevalley-Maurel S, Ozir-Fazalalikhan A, Koppejan H, Winkel BMF, Ramesar J, Khan SM, Sauerwein RW, Roestenberg M, Janse CJ, Smits HH, Franke-Fayard B. Protective immunity differs between routes of administration of attenuated malaria parasites independent of parasite liver load. Sci Rep 2017; 7:10372. [PMID: 28871201 PMCID: PMC5583236 DOI: 10.1038/s41598-017-10480-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/10/2017] [Indexed: 12/27/2022] Open
Abstract
In humans and murine models of malaria, intradermal immunization (ID-I) with genetically attenuated sporozoites that arrest in liver induces lower protective immunity than intravenous immunization (IV-I). It is unclear whether this difference is caused by fewer sporozoites migrating into the liver or by suboptimal hepatic and injection site-dependent immune responses. We therefore developed a Plasmodium yoelii immunization/boost/challenge model to examine parasite liver loads as well as hepatic and lymph node immune responses in protected and unprotected ID-I and IV-I animals. Despite introducing the same numbers of genetically attenuated parasites in the liver, ID-I resulted in lower sterile protection (53-68%) than IV-I (93-95%). Unprotected mice developed less sporozoite-specific CD8+ and CD4+ effector T-cell responses than protected mice. After immunization, ID-I mice showed more interleukin-10-producing B and T cells in livers and skin-draining lymph nodes, but fewer hepatic CD8 memory T cells and CD8+ dendritic cells compared to IV-I mice. Our results indicate that the lower protection efficacy obtained by intradermal sporozoite administration is not linked to low hepatic parasite numbers as presumed before, but correlates with a shift towards regulatory immune responses. Overcoming these immune suppressive responses is important not only for live-attenuated malaria vaccines but also for other live vaccines administered in the skin.
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Affiliation(s)
- Simone Haeberlein
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.,Institute of Parasitology, Justus-Liebig-University Giessen, Schubertstrasse 81, 35392, Giessen, Germany
| | - Séverine Chevalley-Maurel
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Arifa Ozir-Fazalalikhan
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Hester Koppejan
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Beatrice M F Winkel
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Jai Ramesar
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Shahid M Khan
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.,Department of Infectious Diseases, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Chris J Janse
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Hermelijn H Smits
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Blandine Franke-Fayard
- Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
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Jaijyan DK, Singh H, Singh AP. A Sporozoite- and Liver Stage-expressed Tryptophan-rich Protein Plays an Auxiliary Role in Plasmodium Liver Stage Development and Is a Potential Vaccine Candidate. J Biol Chem 2015; 290:19496-511. [PMID: 25960542 DOI: 10.1074/jbc.m114.588129] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Indexed: 01/07/2023] Open
Abstract
The liver stages of the malaria parasite are clinically silent and constitute ideal targets for causal prophylactic drugs and vaccines. Cellular and molecular events responsible for liver stage development are poorly characterized. Here, we show that sporozoite, liver stage tryptophan-rich protein (SLTRiP) forms large multimers. Mice immunized with a purified recombinant SLTRiP protein gave high antibody titers in both inbred and outbred mice. Immunized mice showed highly significant levels of protection upon challenge with sporozoites and exhibited 10,000-fold fewer parasite 18S-rRNA copy numbers in their livers. The protection offered by immunization with SLTRiP came mainly from T-cells, and antibodies had little role to play despite their high titers. Immunofluorescence assays showed that SLTRiP is expressed in the sporozoite and early to late liver stages of malaria parasites. SLTRiP protein is exported to the cytosol of infected host cells during the early hours of parasite infection. Parasites deficient in SLTRiP were moderately defective in liver stage parasite development. A transcriptome profile of SLTRiP-deficient parasite-infected hepatocytes highlighted that SLTRiP interferes with multiple pathways in the host cell. We have demonstrated a role for SLTRiP in sporozoites and the liver stage of malaria parasites.
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Affiliation(s)
- Dabbu Kumar Jaijyan
- From the Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Himanshu Singh
- From the Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Agam Prasad Singh
- From the Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
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Pinzon-Charry A, Woodberry T, Kienzle V, McPhun V, Minigo G, Lampah DA, Kenangalem E, Engwerda C, López JA, Anstey NM, Good MF. Apoptosis and dysfunction of blood dendritic cells in patients with falciparum and vivax malaria. ACTA ACUST UNITED AC 2013; 210:1635-46. [PMID: 23835848 PMCID: PMC3727318 DOI: 10.1084/jem.20121972] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Acute Plasmodium infections in humans result in dendritic cell dysfunction and apoptosis caused in part by elevated levels of IL-10. Malaria causes significant morbidity worldwide and a vaccine is urgently required. Plasmodium infection causes considerable immune dysregulation, and elicitation of vaccine immunity remains challenging. Given the central role of dendritic cells (DCs) in initiating immunity, understanding their biology during malaria will improve vaccination outcomes. Circulating DCs are particularly important, as they shape immune responses in vivo and reflect the functional status of other subpopulations. We performed cross-sectional and longitudinal assessments of the frequency, phenotype, and function of circulating DC in 67 Papuan adults during acute uncomplicated P. falciparum, P. vivax, and convalescent P. falciparum infections. We demonstrate that malaria patients display a significant reduction in circulating DC numbers and the concurrent accumulation of immature cells. Such alteration is associated with marked levels of spontaneous apoptosis and impairment in the ability of DC to mature, capture, and present antigens to T cells. Interestingly, sustained levels of plasma IL-10 were observed in patients with acute infection and were implicated in the induction of DC apoptosis. DC apoptosis was reversed upon IL-10 blockade, and DC function recovered when IL-10 levels returned to baseline by convalescence. Our data provide key information on the mechanisms behind DC suppression during malaria and will assist in developing strategies to better harness DC’s immunotherapeutic potential.
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Sheehy SH, Douglas AD, Draper SJ. Challenges of assessing the clinical efficacy of asexual blood-stage Plasmodium falciparum malaria vaccines. Hum Vaccin Immunother 2013; 9:1831-40. [PMID: 23778312 PMCID: PMC3906345 DOI: 10.4161/hv.25383] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In the absence of any highly effective vaccine candidate against Plasmodium falciparum malaria, it remains imperative for the field to pursue all avenues that may lead to the successful development of such a formulation. The development of a subunit vaccine targeting the asexual blood-stage of Plasmodium falciparum malaria infection has proven particularly challenging with only limited success to date in clinical trials. However, only a fraction of potential blood-stage vaccine antigens have been evaluated as targets, and a number of new promising candidate antigen formulations and delivery platforms are approaching clinical development. It is therefore essential that reliable and sensitive methods of detecting, or ruling out, even modest efficacy of blood-stage vaccines in small clinical trials be established. In this article we evaluate the challenges facing blood-stage vaccine developers, assess the appropriateness and limitations of various in vivo approaches for efficacy assessment and suggest future directions for the field.
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7
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The species specificity of immunity generated by live whole organism immunisation with erythrocytic and pre-erythrocytic stages of rodent malaria parasites and implications for vaccine development. Int J Parasitol 2012; 42:859-70. [DOI: 10.1016/j.ijpara.2012.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/29/2012] [Accepted: 07/03/2012] [Indexed: 11/20/2022]
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8
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Annoura T, Ploemen IHJ, van Schaijk BCL, Sajid M, Vos MW, van Gemert GJ, Chevalley-Maurel S, Franke-Fayard BMD, Hermsen CC, Gego A, Franetich JF, Mazier D, Hoffman SL, Janse CJ, Sauerwein RW, Khan SM. Assessing the adequacy of attenuation of genetically modified malaria parasite vaccine candidates. Vaccine 2012; 30:2662-70. [PMID: 22342550 DOI: 10.1016/j.vaccine.2012.02.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 02/02/2012] [Accepted: 02/03/2012] [Indexed: 11/30/2022]
Abstract
The critical first step in the clinical development of a malaria vaccine, based on live-attenuated Plasmodium falciparum sporozoites, is the guarantee of complete arrest in the liver. We report on an approach for assessing adequacy of attenuation of genetically attenuated sporozoites in vivo using the Plasmodium berghei model of malaria and P. falciparum sporozoites cultured in primary human hepatocytes. We show that two genetically attenuated sporozoite vaccine candidates, Δp52+p36 and Δfabb/f, are not adequately attenuated. Sporozoites infection of mice with both P. berghei candidates can result in blood infections. We also provide evidence that P. falciparum sporozoites of the leading vaccine candidate that is similarly attenuated through the deletion of the genes encoding the proteins P52 and P36, can develop into replicating liver stages. Therefore, we propose a minimal set of screening criteria to assess adequacy of sporozoite attenuation necessary before advancing into further clinical development and studies in humans.
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Affiliation(s)
- Takeshi Annoura
- Leiden Malaria Research Group, Department of Parasitology, Leiden University Medical Center, 2333 ZA Leiden, Netherlands
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9
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Gerald NJ, Majam V, Mahajan B, Kozakai Y, Kumar S. Protection from experimental cerebral malaria with a single dose of radiation-attenuated, blood-stage Plasmodium berghei parasites. PLoS One 2011; 6:e24398. [PMID: 21935405 PMCID: PMC3174172 DOI: 10.1371/journal.pone.0024398] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 08/08/2011] [Indexed: 12/31/2022] Open
Abstract
Background Whole malaria parasites are highly effective in inducing immunity against malaria. Due to the limited success of subunit based vaccines in clinical studies, there has been a renewed interest in whole parasite-based malaria vaccines. Apart from attenuated sporozoites, there have also been efforts to use live asexual stage parasites as vaccine immunogens. Methodology and Results We used radiation exposure to attenuate the highly virulent asexual blood stages of the murine malaria parasite P. berghei to a non-replicable, avirulent form. We tested the ability of the attenuated blood stage parasites to induce immunity to parasitemia and the symptoms of severe malaria disease. Depending on the mouse genetic background, a single high dose immunization without adjuvant protected mice from parasitemia and severe disease (CD1 mice) or from experimental cerebral malaria (ECM) (C57BL/6 mice). A low dose immunization did not protect against parasitemia or severe disease in either model after one or two immunizations. The protection from ECM was associated with a parasite specific antibody response and also with a lower level of splenic parasite-specific IFN-γ production, which is a mediator of ECM pathology in C57BL/6 mice. Surprisingly, there was no difference in the sequestration of CD8+ T cells and CD45+ CD11b+ macrophages in the brains of immunized, ECM-protected mice. Conclusions This report further demonstrates the effectiveness of a whole parasite blood-stage vaccine in inducing immunity to malaria and explicitly demonstrates its effectiveness against ECM, the most pathogenic consequence of malaria infection. This experimental model will be important to explore the formulation of whole parasite blood-stage vaccines against malaria and to investigate the immune mechanisms that mediate protection against parasitemia and cerebral malaria.
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Affiliation(s)
- Noel J. Gerald
- Division of Emerging Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, Maryland, United States of America
| | - Victoria Majam
- Division of Emerging Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, Maryland, United States of America
| | - Babita Mahajan
- Division of Emerging Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, Maryland, United States of America
| | - Yukiko Kozakai
- Division of Emerging Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, Maryland, United States of America
| | - Sanjai Kumar
- Division of Emerging Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, Maryland, United States of America
- * E-mail:
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Goodman AL, Draper SJ. Blood-stage malaria vaccines - recent progress and future challenges. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2010; 104:189-211. [PMID: 20507694 DOI: 10.1179/136485910x12647085215534] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Plasmodium falciparum malaria is a major global health problem, responsible for up to 1 million deaths each year. Major efforts have been made to develop an effective vaccine against this disease, to reduce the associated morbidity and mortality. There has already been considerable progress, with the first vaccine against the pre-erythrocytic stages of P. falciparum now en route to licensure. There remains, however, a strong scientific rationale for the development of a highly effective additional vaccine component against the blood stages of the parasite, which could be deployed in conjunction with partially effective control measures against the pre-erythrocytic stages. Here, recent progress in the clinical development of blood-stage vaccines is reviewed, including methods of antigen selection, the limitations of in-vitro assays for selecting vaccines for clinical development, and the results of recently published clinical trials. This review seeks to summarize recent developments in our understanding of immunity to blood-stage parasites, as well as the relevant key advances made in vaccine technologies over the last decade. The future challenges that face this field of vaccine research are also described.
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Affiliation(s)
- A L Goodman
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK.
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Sedegah M, Rogers WO, Belmonte M, Belmonte A, Banania G, Patterson NB, Rusalov D, Ferrari M, Richie TL, Doolan DL. Vaxfectin® enhances both antibody and in vitro T cell responses to each component of a 5-gene Plasmodium falciparum plasmid DNA vaccine mixture administered at low doses. Vaccine 2010; 28:3055-65. [DOI: 10.1016/j.vaccine.2009.10.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 10/08/2009] [Accepted: 10/12/2009] [Indexed: 10/20/2022]
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12
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Affiliation(s)
- Anthony A Holder
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom.
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13
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Cavalli A, Lizzi F, Bongarzone S, Belluti F, Piazzi L, Bolognesi ML. Complementary medicinal chemistry-driven strategies toward new antitrypanosomal and antileishmanial lead drug candidates. ACTA ACUST UNITED AC 2009; 58:51-60. [PMID: 19845762 DOI: 10.1111/j.1574-695x.2009.00615.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trypanosomiases and Leishmaniases are neglected tropical diseases that affect the less developed countries. For this reason, they did not and still do not have high visibility in Western societies. The name neglected diseases also refers to the fact that they often received little interest at the level of public investment, research and development. The drug discovery scenario, however, is changing dramatically. After a period in which different socioeconomic factors have prevented massive research efforts in this field, such efforts have increased considerably in the very recent years, with significant scientific advancements. In this context, we have embarked on a new drug discovery project devoted to identification of new small molecules for the treatment of trypanosomal and leishmanial diseases. Two complementary approaches have been pursued and are reported here. The first deals with a structure-based drug design, and a privileged structure-guided synthesis of quinazoline compounds able to modulate trypanothione reductase activity was accomplished. In the second, a combinatorial library, built on a natural product-based strategy, was synthesized. Using whole parasite assays, different quinones have been identified as promising lead compounds. A combination of both approaches to hopefully overcome some of the challenges of anti-trypanosomatid drug discovery has eventually been proposed.
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Affiliation(s)
- Andrea Cavalli
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy
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14
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Kun JF, de Carvalho EG. Novel therapeutic targets in Plasmodium falciparum: aquaglyceroporins. Expert Opin Ther Targets 2009; 13:385-94. [PMID: 19335062 DOI: 10.1517/14728220902817839] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Malaria is caused by the intracellular parasite Plasmodium falciparum. The constant need for novel malaria therapies is due to the development of resistance against existing drugs. OBJECTIVE To summarise attempts to investigate parasitic aquaporins as drug targets in malaria. METHODS Starting with a summary of the history of malaria we present aquaporin structure and function relationships. Potential interactions of inhibitors with plasmodial AQP (PfAQP) are discussed. PfAQP blockage is examined in the light of recent work on knock-out parasites. Since PfAQP is able to transport other small solutes the parasites are sensitive to other compounds which are harmless to the human host. RESULTS/CONCLUSIONS Total blockage of PfAQP may not lead to the death of the parasite but application of PfAQP as a vehicle for toxic substances may be a further pathway for research.
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Affiliation(s)
- Jürgen F Kun
- Department of Parasitology, Institute for Tropical Medicine, Tübingen, Germany.
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16
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Good MF. The hope but challenge for developing a vaccine that might control malaria. Eur J Immunol 2009; 39:939-43. [DOI: 10.1002/eji.200939390] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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17
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Malaria vaccines: into a mirror, darkly? Trends Parasitol 2008; 24:532-6. [DOI: 10.1016/j.pt.2008.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 09/08/2008] [Accepted: 09/10/2008] [Indexed: 12/25/2022]
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van Schaijk BCL, Janse CJ, van Gemert GJ, van Dijk MR, Gego A, Franetich JF, van de Vegte-Bolmer M, Yalaoui S, Silvie O, Hoffman SL, Waters AP, Mazier D, Sauerwein RW, Khan SM. Gene disruption of Plasmodium falciparum p52 results in attenuation of malaria liver stage development in cultured primary human hepatocytes. PLoS One 2008; 3:e3549. [PMID: 18958160 PMCID: PMC2568858 DOI: 10.1371/journal.pone.0003549] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 10/07/2008] [Indexed: 11/19/2022] Open
Abstract
Difficulties with inducing sterile and long lasting protective immunity against malaria with subunit vaccines has renewed interest in vaccinations with attenuated Plasmodium parasites. Immunizations with sporozoites that are attenuated by radiation (RAS) can induce strong protective immunity both in humans and rodent models of malaria. Recently, in rodent parasites it has been shown that through the deletion of a single gene, sporozoites can also become attenuated in liver stage development and, importantly, immunization with these sporozoites results in immune responses identical to RAS. The promise of vaccination using these genetically attenuated sporozoites (GAS) depends on translating the results in rodent malaria models to human malaria. In this study, we perform the first essential step in this transition by disrupting, p52, in P. falciparum an ortholog of the rodent parasite gene, p36p, which we had previously shown can confer long lasting protective immunity in mice. These P. falciparum P52 deficient sporozoites demonstrate gliding motility, cell traversal and an invasion rate into primary human hepatocytes in vitro that is comparable to wild type sporozoites. However, inside the host hepatocyte development is arrested very soon after invasion. This study reveals, for the first time, that disrupting the equivalent gene in both P. falciparum and rodent malaria Plasmodium species generates parasites that become similarly arrested during liver stage development and these results pave the way for further development of GAS for human use.
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Affiliation(s)
- Ben C. L. van Schaijk
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Chris J. Janse
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Melissa R. van Dijk
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Audrey Gego
- INSERM, U511, Paris, France
- Université Pierre et Marie Curie-Paris6, UMR S511 Paris, France
| | | | - Marga van de Vegte-Bolmer
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Samir Yalaoui
- INSERM, U511, Paris, France
- Université Pierre et Marie Curie-Paris6, UMR S511 Paris, France
| | - Olivier Silvie
- INSERM, U511, Paris, France
- Université Pierre et Marie Curie-Paris6, UMR S511 Paris, France
| | | | - Andrew P. Waters
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Dominique Mazier
- INSERM, U511, Paris, France
- Université Pierre et Marie Curie-Paris6, UMR S511 Paris, France
- AP-HP, Groupe hospitalier Pitié-Salpêtrière, Service Parasitologie-Mycologie, Paris, France
| | - Robert W. Sauerwein
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Shahid M. Khan
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
- * E-mail:
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