1
|
Beyeler R, Jordan M, Dorner L, He B, Cyrklaff M, Roques M, Stanway R, Frischknecht F, Heussler V. Putative prefoldin complex subunit 5 of Plasmodium berghei is crucial for microtubule formation and parasite development in the mosquito. Mol Microbiol 2024; 121:481-496. [PMID: 38009402 DOI: 10.1111/mmi.15196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 09/11/2023] [Accepted: 11/01/2023] [Indexed: 11/28/2023]
Abstract
Plasmodium sporozoite development in and egress from oocysts in the Anopheles mosquito remains largely enigmatic. In a previously performed high-throughput knockout screen, the putative subunit 5 of the prefoldin complex (PbPCS5, PBANKA_0920100) was identified as essential for parasite development during mosquito and liver stage development. Here we generated and analyzed a PbPCS5 knockout parasite line during its development in the mosquito. Interestingly, PbPCS5 deletion does not significantly affect oocyst formation but leads to a growth defect resulting in aberrantly shaped sporozoites. Sporozoites produced in the absence of PbPCS5 were thinner, markedly elongated, and did, in most cases, not contain a nucleus. Sporozoites contained fewer subpellicular microtubules, which reached deep into the sporoblast during sporogony where they contacted and indented nuclei. These aberrantly shaped sporozoites did not reach the salivary glands, and we, therefore, conclude that PbPCS5 is essential for sporogony and the life cycle progression of the parasite during its mosquito stage.
Collapse
Affiliation(s)
- Raphael Beyeler
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Melanie Jordan
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School, Heidelberg, Germany
| | - Lilian Dorner
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School, Heidelberg, Germany
| | - Buyuan He
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School, Heidelberg, Germany
| | - Marek Cyrklaff
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School, Heidelberg, Germany
| | - Magali Roques
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Rebecca Stanway
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, University of Heidelberg Medical School, Heidelberg, Germany
- German Center for Infection Research, DZIF Partner Site Heidelberg, Heidelberg, Germany
| | - Volker Heussler
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| |
Collapse
|
2
|
Immunization with full-length Plasmodium falciparum merozoite surface protein 1 is safe and elicits functional cytophilic antibodies in a randomized first-in-human trial. NPJ Vaccines 2020; 5:10. [PMID: 32025341 PMCID: PMC6994672 DOI: 10.1038/s41541-020-0160-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/14/2020] [Indexed: 12/20/2022] Open
Abstract
A vaccine remains a priority in the global fight against malaria. Here, we report on a single-center, randomized, double-blind, placebo and adjuvant-controlled, dose escalation phase 1a safety and immunogenicity clinical trial of full-length Plasmodium falciparum merozoite surface protein 1 (MSP1) in combination with GLA-SE adjuvant. Thirty-two healthy volunteers were vaccinated at least three times with MSP1 plus adjuvant, adjuvant alone, or placebo (24:4:4) to evaluate the safety and immunogenicity. MSP1 was safe, well tolerated and immunogenic, with all vaccinees sero-converting independent of the dose. The MSP1-specific IgG and IgM titers persisted above levels found in malaria semi-immune humans for at least 6 months after the last immunization. The antibodies were variant- and strain-transcending and stimulated respiratory activity in granulocytes. Furthermore, full-length MSP1 induced memory T-cells. Our findings encourage challenge studies as the next step to evaluate the efficacy of full-length MSP1 as a vaccine candidate against falciparum malaria (EudraCT 2016-002463-33).
Collapse
|
3
|
Kano FS, de Souza AM, de Menezes Torres L, Costa MA, Souza-Silva FA, Sanchez BAM, Fontes CJF, Soares IS, de Brito CFA, Carvalho LH, Sousa TN. Susceptibility to Plasmodium vivax malaria associated with DARC (Duffy antigen) polymorphisms is influenced by the time of exposure to malaria. Sci Rep 2018; 8:13851. [PMID: 30218021 PMCID: PMC6138695 DOI: 10.1038/s41598-018-32254-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/03/2018] [Indexed: 11/28/2022] Open
Abstract
Malaria has provided a major selective pressure and has modulated the genetic diversity of the human genome. The variants of the Duffy Antigen/Receptor for Chemokines (DARC) gene have probably been selected by malaria parasites, particularly the FY*O allele, which is fixed in sub-Saharan Africa and confers resistance to Plasmodium vivax infection. Here, we showed the influence of genomic ancestry on the distribution of DARC genotypes in a highly admixed Brazilian population and confirmed the decreased susceptibility of the FY*A/FY*O genotype to clinical P. vivax malaria. FY*B/FY*O individuals were associated with a greater risk of developing clinical malaria. A remarkable difference among DARC variants concerning the susceptibility to clinical malaria was more evident for individuals who were less exposed to malaria, as measured by the time of residence in the endemic area. Additionally, we found that DARC-negative and FY*A/FY*O individuals had a greater chance of acquiring high levels of antibodies against the 19-kDa C-terminal region of the P. vivax merozoite surface protein-1. Altogether, our results provide evidence that DARC polymorphisms modulate the susceptibility to clinical P. vivax malaria and influence the naturally-acquired humoral immune response to malaria blood antigens, which may interfere with the efficacy of a future vaccine against malaria.
Collapse
Affiliation(s)
- Flora Satiko Kano
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Aracele Maria de Souza
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Leticia de Menezes Torres
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Marcelo Azevedo Costa
- Departamento de Engenharia de Produção, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Flávia Alessandra Souza-Silva
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | | | | | - Irene Silva Soares
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Cristiana Ferreira Alves de Brito
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Luzia Helena Carvalho
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil
| | - Tais Nobrega Sousa
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil.
| |
Collapse
|
4
|
Loy DE, Rubel MA, Avitto AN, Liu W, Li Y, Learn GH, Ranciaro A, Mbunwe E, Fokunang C, Njamnshi AK, Sharp PM, Tishkoff SA, Hahn BH. Investigating zoonotic infection barriers to ape Plasmodium parasites using faecal DNA analysis. Int J Parasitol 2018; 48:531-542. [PMID: 29476866 DOI: 10.1016/j.ijpara.2017.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/09/2017] [Accepted: 12/15/2017] [Indexed: 01/17/2023]
Abstract
African apes are endemically infected with numerous Plasmodium spp. including close relatives of human Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. Although these ape parasites are not believed to pose a zoonotic threat, their ability to colonise humans has not been fully explored. In particular, it remains unknown whether ape parasites are able to initiate exo-erythrocytic replication in human hepatocytes following the bite of an infective mosquito. Since animal studies have shown that liver stage infection can result in the excretion of parasite nucleic acids into the bile, we screened faecal samples from 504 rural Cameroonians for Plasmodium DNA. Using pan-Laverania as well as P. malariae- and P. vivax-specific primer sets, we amplified human P. falciparum (n = 14), P. malariae (n = 1), and P. ovale wallikeri (n = 1) mitochondrial sequences from faecal DNA of 15 individuals. However, despite using an intensified PCR screening approach we failed to detect ape Laverania, ape P. vivax or ape P. malariae parasites in these same subjects. One faecal sample from a hunter-gatherer contained a sequence closely related to the porcupine parasite Plasmodium atheruri. Since this same faecal sample also contained porcupine mitochondrial DNA, but a matching blood sample was Plasmodium-negative, it is likely that this hunter-gatherer consumed Plasmodium-infected bushmeat. Faecal Plasmodium detection was not secondary to intestinal bleeding and/or infection with gastrointestinal parasites, but indicative of blood parasitaemia. Quantitative PCR identified 26-fold more parasite DNA in the blood of faecal Plasmodium-positive than faecal Plasmodium-negative individuals (P = 0.01). However, among blood-positive individuals only 10% - 20% had detectable Plasmodium sequences in their stool. Thus, faecal screening of rural Cameroonians failed to uncover abortive ape Plasmodium infections, but detected infection with human parasites, albeit with reduced sensitivity compared with blood analysis.
Collapse
Affiliation(s)
- Dorothy E Loy
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Meagan A Rubel
- Department of Anthropology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexa N Avitto
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Weimin Liu
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yingying Li
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gerald H Learn
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alessia Ranciaro
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eric Mbunwe
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charles Fokunang
- Department of Pharmacotoxicology and Pharmacokinetics, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Alfred K Njamnshi
- Department of Neurology, Faculty of Medicine and Biomedical Sciences, Central Hospital Yaoundé, University of Yaoundé I, Yaoundé, Cameroon
| | - Paul M Sharp
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom
| | - Sarah A Tishkoff
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Beatrice H Hahn
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
5
|
A chimeric protein-based malaria vaccine candidate induces robust T cell responses against Plasmodium vivax MSP1 19. Sci Rep 2016; 6:34527. [PMID: 27708348 PMCID: PMC5052570 DOI: 10.1038/srep34527] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 09/15/2016] [Indexed: 01/06/2023] Open
Abstract
The most widespread Plasmodium species, Plasmodium vivax, poses a significant public health threat. An effective vaccine is needed to reduce global malaria burden. Of the erythrocytic stage vaccine candidates, the 19 kDa fragment of the P. vivax Merozoite Surface Protein 1 (PvMSP119) is one of the most promising. Our group has previously defined several promiscuous T helper epitopes within the PvMSP1 protein, with features that allow them to bind multiple MHC class II alleles. We describe here a P. vivax recombinant modular chimera based on MSP1 (PvRMC-MSP1) that includes defined T cell epitopes genetically fused to PvMSP119. This vaccine candidate preserved structural elements of the native PvMSP119 and elicited cytophilic antibody responses, and CD4+ and CD8+ T cells capable of recognizing PvMSP119. Although CD8+ T cells that recognize blood stage antigens have been reported to control blood infection, CD8+ T cell responses induced by P. falciparum or P. vivax vaccine candidates based on MSP119 have not been reported. To our knowledge, this is the first time a protein based subunit vaccine has been able to induce CD8+ T cell against PvMSP119. The PvRMC-MSP1 protein was also recognized by naturally acquired antibodies from individuals living in malaria endemic areas with an antibody profile associated with protection from infection. These features make PvRMC-MSP1 a promising vaccine candidate.
Collapse
|
6
|
Nahrendorf W, Scholzen A, Sauerwein RW, Langhorne J. Cross-stage immunity for malaria vaccine development. Vaccine 2015; 33:7513-7. [PMID: 26469724 PMCID: PMC4687527 DOI: 10.1016/j.vaccine.2015.09.098] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 09/11/2015] [Accepted: 09/28/2015] [Indexed: 11/17/2022]
Abstract
A vaccine against malaria is urgently needed for control and eventual eradication. Different approaches are pursued to induce either sterile immunity directed against pre-erythrocytic parasites or to mimic naturally acquired immunity by controlling blood-stage parasite densities and disease severity. Pre-erythrocytic and blood-stage malaria vaccines are often seen as opposing tactics, but it is likely that they have to be combined into a multi-stage malaria vaccine to be optimally safe and effective. Since many antigenic targets are shared between liver- and blood-stage parasites, malaria vaccines have the potential to elicit cross-stage protection with immune mechanisms against both stages complementing and enhancing each other. Here we discuss evidence from pre-erythrocytic and blood-stage subunit and whole parasite vaccination approaches that show that protection against malaria is not necessarily stage-specific. Parasites arresting at late liver-stages especially, can induce powerful blood-stage immunity, and similarly exposure to blood-stage parasites can afford pre-erythrocytic immunity. The incorporation of a blood-stage component into a multi-stage malaria vaccine would hence not only combat breakthrough infections in the blood should the pre-erythrocytic component fail to induce sterile protection, but would also actively enhance the pre-erythrocytic potency of this vaccine. We therefore advocate that future studies should concentrate on the identification of cross-stage protective malaria antigens, which can empower multi-stage malaria vaccine development.
Collapse
Affiliation(s)
- Wiebke Nahrendorf
- Mill Hill Laboratory, The Francis Crick Institute, London, United Kingdom; Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Anja Scholzen
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Jean Langhorne
- Mill Hill Laboratory, The Francis Crick Institute, London, United Kingdom.
| |
Collapse
|
7
|
Daou M, Kouriba B, Ouédraogo N, Diarra I, Arama C, Keita Y, Sissoko S, Ouologuem B, Arama S, Bousema T, Doumbo OK, Sauerwein RW, Scholzen A. Protection of Malian children from clinical malaria is associated with recognition of multiple antigens. Malar J 2015; 14:56. [PMID: 25653026 PMCID: PMC4332451 DOI: 10.1186/s12936-015-0567-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 01/16/2015] [Indexed: 12/13/2022] Open
Abstract
Background Naturally acquired immunity to clinical malaria is thought to be mainly antibody-mediated, but reports on antigen targets are contradictory. Recognition of multiple antigens may be crucial for protection. In this study, the magnitude of antibody responses and their temporal stability was assessed for a panel of malaria antigens in relation to protection against clinical Plasmodium falciparum malaria. Methods Malian children aged two to 14 years were enrolled in a longitudinal study and followed up by passive and active case detection for seven months. Plasma was collected at enrolment and at the beginning, in the middle and after the end of the transmission season. Antibody titres to the P. falciparum-antigens apical membrane protein (AMA)-1, merozoite surface protein (MSP)-119, MSP-3, glutamine-rich protein (GLURP-R0) and circumsporozoite antigen (CSP) were assessed by enzyme-linked immunosorbent assay (ELISA) for 99 children with plasma available at all time points. Parasite carriage was determined by microscopy and nested PCR. Results Antibody titres to all antigens, except MSP-119, and the number of antigens recognized increased with age. After malaria exposure, antibody titres increased in children that had low titres at baseline, but decreased in those with high baseline responses. No significant differences were found between antibody titers for individual antigens between children remaining symptomatic or asymptomatic after exposure, after adjustment for age. Instead, children remaining asymptomatic following parasite exposure had a broader repertoire of antigen recognition. Conclusions The present study provides immune-epidemiological evidence from a limited cohort of Malian children that strong recognition of multiple antigens, rather than antibody titres for individual antigens, is associated with protection from clinical malaria. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0567-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Modibo Daou
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali. .,Department of Medical Microbiology, Radboud university medical center, Route 268, PO Box 9101, 6500, HB Nijmegen, The Netherlands.
| | - Bourèma Kouriba
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Nicolas Ouédraogo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, Burkina Faso.
| | - Issa Diarra
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Charles Arama
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Yamoussa Keita
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Sibiri Sissoko
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Boucary Ouologuem
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Seydou Arama
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Teun Bousema
- Department of Medical Microbiology, Radboud university medical center, Route 268, PO Box 9101, 6500, HB Nijmegen, The Netherlands. .,Department of Infection and Immunity, London School of Hygiene and Tropical Medicine, London, UK.
| | - Ogobara K Doumbo
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Centre, University of Science, Techniques and Technologies of Bamako, Bamako, Mali.
| | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud university medical center, Route 268, PO Box 9101, 6500, HB Nijmegen, The Netherlands.
| | - Anja Scholzen
- Department of Medical Microbiology, Radboud university medical center, Route 268, PO Box 9101, 6500, HB Nijmegen, The Netherlands.
| |
Collapse
|
8
|
Zong S, Kron MW, Epp C, Engler T, Bujard H, Kochanek S, Kreppel F. ΔE1 and high-capacity adenoviral vectors expressing full-length codon-optimized merozoite surface protein 1 for vaccination against Plasmodium falciparum. J Gene Med 2013; 13:670-9. [PMID: 22095915 DOI: 10.1002/jgm.1627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The merozoite surface protein (MSP)-1 of Plasmodium falciparum, the causative agent of malaria tropica, is considered to be a promising vaccine candidate. Although its stable cloning and expression has been difficult in the past, adenoviral vectors expressing the complex protein are described in the present study. METHODS Codon-optimized msp-1 was used to construct a set of first generation (ΔE1Ad) and high-capacity adenovirus (HC-Ad) vectors, and cellular and humoral immune responses induced by the vectors were characterized in detail in mice. RESULTS Generation of stable ΔE1Ad and HC-Ad vectors expressing full-length MSP-1 and their production to high vector titers was found to be feasible. Epitope identification and analysis of frequencies of specific CD8 T-cells revealed that MSP-1 expressing HC-Ad vectors induced higher frequencies of interferon-γ + CD8 T-cells than ΔE1 vectors. Irrespective of the vector format, higher titers of MSP-1 specific antibodies were generated by Ad vectors expressing MSP-1 from a chicken β-actin (CAG) promoter comprising the cytomegalovirus early enhancer element and the chicken β-actin promoter. CONCLUSIONS The findings of the present study suggest that Ad vectors expressing full-length codon-optimized MSP-1 are promising candidate vaccines against P. falciparum infections. Use of the HC-Ad vector type for delivery, as well as the CAG promoter to control MSP-1 expression, may further increase the efficacy of this vaccine candidate.
Collapse
Affiliation(s)
- Shan Zong
- Department of Gene Therapy, University of Ulm, Ulm, Germany
| | | | | | | | | | | | | |
Collapse
|
9
|
Mueller I, Galinski MR, Tsuboi T, Arevalo-Herrera M, Collins WE, King CL. Natural acquisition of immunity to Plasmodium vivax: epidemiological observations and potential targets. ADVANCES IN PARASITOLOGY 2013; 81:77-131. [PMID: 23384622 DOI: 10.1016/b978-0-12-407826-0.00003-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Population studies show that individuals acquire immunity to Plasmodium vivax more quickly than Plasmodium falciparum irrespective of overall transmission intensity, resulting in the peak burden of P. vivax malaria in younger age groups. Similarly, actively induced P. vivax infections in malaria therapy patients resulted in faster and generally more strain-transcending acquisition of immunity than P. falciparum infections. The mechanisms behind the more rapid acquisition of immunity to P. vivax are poorly understood. Natural acquired immune responses to P. vivax target both pre-erythrocytic and blood-stage antigens and include humoral and cellular components. To date, only a few studies have investigated the association of these immune responses with protection, with most studies focussing on a few merozoite antigens (such as the Pv Duffy binding protein (PvDBP), the Pv reticulocyte binding proteins (PvRBPs), or the Pv merozoite surface proteins (PvMSP1, 3 & 9)) or the circumsporozoite protein (PvCSP). Naturally acquired transmission-blocking (TB) immunity (TBI) was also found in several populations. Although limited, these data support the premise that developing a multi-stage P. vivax vaccine may be feasible and is worth pursuing.
Collapse
Affiliation(s)
- Ivo Mueller
- Walter + Eliza Hall Institute, Infection & Immunity Division, Parkville, Victoria, Australia
| | | | | | | | | | | |
Collapse
|
10
|
Hamid MMA, Remarque EJ, El Hassan IM, Hussain AA, Narum DL, Thomas AW, Kocken CHM, Weiss WR, Faber BW. Malaria infection by sporozoite challenge induces high functional antibody titres against blood stage antigens after a DNA prime, poxvirus boost vaccination strategy in Rhesus macaques. Malar J 2011; 10:29. [PMID: 21303498 PMCID: PMC3046915 DOI: 10.1186/1475-2875-10-29] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 02/08/2011] [Indexed: 11/22/2022] Open
Abstract
Background A DNA prime, poxvirus (COPAK) boost vaccination regime with four antigens, i.e. a combination of two Plasmodium knowlesi sporozoite (csp/ssp2) and two blood stage (ama1/msp142) genes, leads to self-limited parasitaemia in 60% of rhesus monkeys and survival from an otherwise lethal infection with P. knowlesi. In the present study, the role of the blood stage antigens in protection was studied in depth, focusing on antibody formation against the blood stage antigens and the functionality thereof. Methods Rhesus macaques were immunized with the four-component vaccine and subsequently challenged i.v. with 100 P. knowlesi sporozoites. During immunization and challenge, antibody titres against the two blood stage antigens were determined, as well as the in vitro growth inhibition capacity of those antibodies. Antigen reversal experiments were performed to determine the relative contribution of antibodies against each of the two blood stage antigens to the inhibition. Results After vaccination, PkAMA1 and PkMSP119 antibody titres in vaccinated animals were low, which was reflected in low levels of inhibition by these antibodies as determined by in vitro inhibition assays. Interestingly, after sporozoite challenge antibody titres against blood stage antigens were boosted over 30-fold in both protected and not protected animals. The in vitro inhibition levels increased to high levels (median inhibitions of 59% and 56% at 6 mg/mL total IgG, respectively). As growth inhibition levels were not significantly different between protected and not protected animals, the ability to control infection appeared cannot be explained by GIA levels. Judged by in vitro antigen reversal growth inhibition assays, over 85% of the inhibitory activity of these antibodies was directed against PkAMA1. Conclusions This is the first report that demonstrates that a DNA prime/poxvirus boost vaccination regimen induces low levels of malaria parasite growth inhibitory antibodies, which are boosted to high levels upon challenge. No association could, however, be established between the levels of inhibitory capacity in vitro and protection, either after vaccination or after challenge.
Collapse
|
11
|
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.
Collapse
Affiliation(s)
- A L Goodman
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK.
| | | |
Collapse
|
12
|
Adenovectors induce functional antibodies capable of potent inhibition of blood stage malaria parasite growth. Vaccine 2010; 28:3201-10. [PMID: 20188680 DOI: 10.1016/j.vaccine.2010.02.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 02/01/2010] [Accepted: 02/10/2010] [Indexed: 11/21/2022]
Abstract
An effective malaria vaccine remains a global health priority. Recombinant adenoviruses are a promising vaccine platform, and Plasmodium falciparum apical membrane antigen 1 (AMA1) and merozoite surface protein 1-42 (MSP1(42)) are leading blood stage vaccine candidates. We evaluated the importance of surface antigen localization and glycosylation on the immunogenicity of adenovector delivered AMA1 and MSP1(42) and assessed the ability of these vaccines to induce functional antibody responses capable of inhibiting parasite growth in vitro. Adenovector delivery induced unprecedented levels of biologically active antibodies in rabbits as indicated by the parasite growth inhibition assay. These responses were as potent as published results using any other vaccine system, including recombinant protein in adjuvant. The cell surface associated and glycosylated forms of AMA1 and MSP1(42) elicited 99% and 60% inhibition of parasite growth, respectively. Antigens that were expressed at the cell surface and glycosylated were much better than intracellular antigens at inducing antibody responses. Good T cell responses were observed for all forms of AMA1 and MSP1(42). Antigen-specific antibody responses, but typically not T cell responses, were boosted by a second administration of adenovector. These data highlight the importance of rational vaccine design and support the advancement of adenovector delivery technology for a malaria vaccine.
Collapse
|
13
|
Abstract
Vaccination remains a crucial component of any initiative to control or eradicate malaria. With increasing reports of insecticide resistance in mosquitoes, and malaria parasite resistance to first-line drugs, it is clear that the development of an effective malaria vaccine is an urgent requirement for the improvement of global human health. This article highlights malaria vaccine research-related discoveries from 2008/9 to suggest that the time is now ripe for researchers to develop malaria vaccines that target many antigens from multiple stages of the parasite’s lifecycle. We also call for greater bidirectional information transfer between preclinical and clinical trials, to facilitate more efficient improvement of malaria vaccine candidates.
Collapse
Affiliation(s)
- Ashraful Haque
- Queensland Institute of Medical Research, 300 Herston Road, Herston, Brisbane, QLD 4006, Australia
| | - Michael F Good
- Queensland Institute of Medical Research, 300 Herston Road, Herston, Brisbane, QLD 4006, Australia
| |
Collapse
|
14
|
Vaughan AM, O'Neill MT, Tarun AS, Camargo N, Phuong TM, Aly ASI, Cowman AF, Kappe SHI. Type II fatty acid synthesis is essential only for malaria parasite late liver stage development. Cell Microbiol 2008; 11:506-20. [PMID: 19068099 PMCID: PMC2688669 DOI: 10.1111/j.1462-5822.2008.01270.x] [Citation(s) in RCA: 287] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Intracellular malaria parasites require lipids for growth and replication. They possess a prokaryotic type II fatty acid synthesis (FAS II) pathway that localizes to the apicoplast plastid organelle and is assumed to be necessary for pathogenic blood stage replication. However, the importance of FAS II throughout the complex parasite life cycle remains unknown. We show in a rodent malaria model that FAS II enzymes localize to the sporozoite and liver stage apicoplast. Targeted deletion of FabB/F, a critical enzyme in fatty acid synthesis, did not affect parasite blood stage replication, mosquito stage development and initial infection in the liver. This was confirmed by knockout of FabZ, another critical FAS II enzyme. However, FAS II-deficient Plasmodium yoelii liver stages failed to form exo-erythrocytic merozoites, the invasive stage that first initiates blood stage infection. Furthermore, deletion of FabI in the human malaria parasite Plasmodium falciparum did not show a reduction in asexual blood stage replication in vitro. Malaria parasites therefore depend on the intrinsic FAS II pathway only at one specific life cycle transition point, from liver to blood.
Collapse
|
15
|
Kaiser K, Camargo N, Kappe SHI. Transformation of sporozoites into early exoerythrocytic malaria parasites does not require host cells. J Exp Med 2003; 197:1045-50. [PMID: 12707302 PMCID: PMC2193875 DOI: 10.1084/jem.20022100] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Malaria parasite species that infect mammals, including humans, must first take up residence in hepatic host cells as exoerythrocytic forms (EEF) before initiating infection of red blood cells that leads to malaria disease. Despite the importance of hepatic stages for immunity against malaria, little is known about their biology and antigenic composition. Here, we show that sporozoites, the parasites' transmission stage that resides in the mosquito vector salivary glands, can transform into early EEF without intracellular residence in host hepatocytes. The morphological sequence of transformation and the expression of proteins in the EEF appear indistinguishable from parasites that develop within host cells. Transformation depends on temperature elevation to 37 degrees C and serum. Our findings demonstrate that residence in a host hepatocyte or specific host cell-derived factors are not necessary to bring about the profound morphological and biochemical changes of the parasite that occur after its transmission from vector to mammalian host.
Collapse
Affiliation(s)
- Karine Kaiser
- Michael Heidelberger Division, Dept. of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | | | | |
Collapse
|
16
|
Kawabata Y, Udono H, Honma K, Ueda M, Mukae H, Kadota JI, Kohno S, Yui K. Merozoite surface protein 1-specific immune response is protective against exoerythrocytic forms of Plasmodium yoelii. Infect Immun 2002; 70:6075-82. [PMID: 12379684 PMCID: PMC130348 DOI: 10.1128/iai.70.11.6075-6082.2002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
One of the difficulties in developing an effective malaria vaccine is the antigenic change of the parasite during the life cycle. It is desirable that vaccine-induced protective immunity be effective at different stages of parasite development. Merozoite surface protein 1 (MSP1) is a candidate vaccine antigen against blood-stage malaria, but it is also expressed in the exoerythrocytic forms. It was not known, however, whether the anti-MSP1 immune response is effective against the liver-stage malaria parasite. We generated a recombinant protein of MSP1 fused to heat-shock cognate protein 70 (hsc70) and studied its vaccination effect. When C57BL/6 mice were immunized with the fusion protein prior to challenge infection with Plasmodium yoelii sporozoites, the onset of parasitemia was delayed or no parasitemia was observed. To determine whether this was due to the protective immunity against liver-stage parasites, P. yoelii-specific rRNA in the infected liver was quantitated by real-time reverse transcription-PCR analysis. The level of parasite-specific rRNA was reduced in mice immunized with the fusion protein of MSP1 and hsc70 but not with hsc70 alone, indicating that MSP1-specific immunity can be protective against the exoerythrocytic form of the parasite. Furthermore, the adoptive transfer experiments of immune lymphocytes and serum into naive mice suggested that the protective immunity was dependent on cellular and not humoral immunity. Finally, the vaccine-induced protection was also observed in A/J, C3H, and BALB/c mice, suggesting that MSP1-specific protective immunity at the exoerythrocytic stage can be induced in animals over a wide range of genetic backgrounds.
Collapse
Affiliation(s)
- Yuko Kawabata
- Division of Immunology, Department of Molecular Medicine, Nagasaki University School of Medicine, Sakamoto, Nagasaki 852-8523, Japan
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Qian F, Pan W. Construction of a tetR-integrated Salmonella enterica serovar Typhi CVD908 strain that tightly controls expression of the major merozoite surface protein of Plasmodium falciparum for applications in human Vaccine production. Infect Immun 2002; 70:2029-38. [PMID: 11895968 PMCID: PMC127878 DOI: 10.1128/iai.70.4.2029-2038.2002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Attenuated Salmonella strains are an attractive live vector for delivery of a foreign antigen to the human immune system. However, the problem with this vector lies with plasmid segregation and the low level of expression of the foreign gene in vivo when constitutive expression is employed, leading to a diminished immune response. We have established inducible expressions of foreign genes in the Salmonella enterica serovar Typhi CVD908 vaccine strain using the tetracycline response regulatory promoter. To set up this system, a tetracycline repressor (tetR) was integrated into a defined Delta aroC locus of the chromosome via suicide plasmid pJG12/tetR-neo. To remove the neo gene conferring kanamycin resistance from the locus, a cre expression vector under the control of the tetracycline response promoter was transformed into the clone; expression of the Cre recombinase excised the neo gene and generated the end strain CVD908-tetR. Expression of the luciferase reporter gene in this strain is dependent on the presence of tetracycline in the medium and can be regulated up to 4,773-fold. Moreover, the tightly controlled expression of major merozoite surface protein 1 (MSP1) and parts of Plasmodium falciparum was achieved, and the product yield was increased when the inducible expression system was employed. Inoculation of bacteria harboring plasmid pZE11/MSP1(42) in mice produced the protein in liver and spleen controlled by the inducer. The persistence of the plasmid-carrying bacteria in mice was determined. Peak colonization of both liver and spleen was detected on the third day postinoculation and was followed by a decline in growth curves. After 14 days postinfection, the majority of the bacteria (>90%) recovered from the liver and spleen of the mice retained the plasmid when expression was induced; this clearly indicated that stability of the expression vector in vivo was improved by inducible expression. Establishment of the regulatory system in the vaccine strain may broaden the range of its use by enhancing plasmid stability and expression levels in vivo. Moreover, the availability of the vaccine strain inducibly expressing the entire MSP1 provides possibilities for examining its immunogenicity, particularly the cellular response in animal models.
Collapse
Affiliation(s)
- Feng Qian
- Department of Etiologic Biology, Second Military Medical University, Shanghai, China
| | | |
Collapse
|
18
|
Kumar S, Villinger F, Oakley M, Aguiar JC, Jones TR, Hedstrom RC, Gowda K, Chute J, Stowers A, Kaslow DC, Thomas EK, Tine J, Klinman D, Hoffman SL, Weiss WW. A DNA vaccine encoding the 42 kDa C-terminus of merozoite surface protein 1 of Plasmodium falciparum induces antibody, interferon-gamma and cytotoxic T cell responses in rhesus monkeys: immuno-stimulatory effects of granulocyte macrophage-colony stimulating factor. Immunol Lett 2002; 81:13-24. [PMID: 11841841 DOI: 10.1016/s0165-2478(01)00316-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have constructed a DNA plasmid vaccine encoding the C-terminal 42-kDa region of the merozoite surface protein 1 (pMSP1(42)) from the 3D7 strain of Plasmodium falciparum (Pf3D7). This plasmid expressed recombinant MSP1(42) after in vitro transfection in mouse VM92 cells. Rhesus monkeys immunized with pMSP1(42) produced antibodies reactive with Pf3D7 infected erythrocytes by IFAT, and by ELISA against yeast produced MSP1(19) (yMSP1(19)). Immunization also induced antigen specific T cell responses as measured by interferon-gamma production, and by classical CTL chromium release assays. In addition, immunization with pMSP1(42) primed animals for an enhanced antibody response to a subsequent boost with the recombinant yMSP1(19). We also evaluated Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) as an adjuvant for pMSP1(42.) We tested both rhesus GM-CSF expressed from a DNA plasmid, and E. coli produced recombinant human GM-CSF. Plasmids encoding rhesus GM-CSF (prhGM-CSF) and human GM-CSF (phuGM-CSF) were constructed; these plasmids expressed bio-active recombinant GMCSF. Co-immunization with a mixture of prhGM-CSF and pMSP1(42) induced higher specific antibody responses after the first dose of plasmid, but after three doses of DNA monkeys immunized with or without prhGM-CSF had the same final antibody titers and T cell responses. In comparison, rhuGM-CSF protein did not lead to accelerated antibody production after the first DNA dose. However, antibody titers were maintained at a slightly higher level in monkeys receiving GM-CSF protein, and they had a higher response to boosting with recombinant MSP1(19). The GM-CSF plasmid or protein appears to be less potent as an adjuvant in rhesus monkeys than each is in mice, and more work is needed to determine if GM-CSF can be a useful adjuvant in DNA vaccination of primates.
Collapse
Affiliation(s)
- Sanjai Kumar
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Heppner DG, Cummings JF, Ockenhouse C, Kester KE, Lyon JA, Gordon DM. New World monkey efficacy trials for malaria vaccine development: critical path or detour? Trends Parasitol 2001; 17:419-25. [PMID: 11530353 DOI: 10.1016/s1471-4922(01)02012-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Neither GMP malaria antigens nor GMP vaccines have been compared for efficacy in monkeys and humans. It is too risky to base categorical (go/no go) development decisions on results obtained using partially characterized (non-GMP) antigens, adjuvants that are too toxic for human use or unvalidated primate models. Such practices will lead to serious errors (e.g. failure to identify and stop flawed efforts, rejection of effective vaccine strategies) and unjustifiable delays. Successful malaria vaccine development will emphasize definitive field trials in populations at risk of malaria to define and improve vaccine efficacy.
Collapse
Affiliation(s)
- D G Heppner
- Malaria Vaccine Program, Division of Communicable Diseases and Immunology, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA.
| | | | | | | | | | | |
Collapse
|
20
|
Rénia L, Ling IT, Marussig M, Miltgen F, Holder AA, Mazier D. Immunization with a recombinant C-terminal fragment of Plasmodium yoelii merozoite surface protein 1 protects mice against homologous but not heterologous P. yoelii sporozoite challenge. Infect Immun 1997; 65:4419-23. [PMID: 9353014 PMCID: PMC175635 DOI: 10.1128/iai.65.11.4419-4423.1997] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
It has been reported previously that immunization with recombinant protein containing the two epidermal growth factor (EGF)-like modules from merozoite surface protein 1 (MSP-1) of Plasmodium yoelii (strain YM) protects mice against a lethal blood-stage challenge with the same parasite strain. Since MSP-1 is expressed in both liver- and blood-stage schizonts and on the surface of merozoites, we evaluated the effectiveness of immunization with recombinant proteins containing either the individual or the two combined EGF-like modules in producing a protective response against a sporozoite challenge. The recombinant protein expressing the combined EGF-like modules of the YM strain protected mice against a homologous sporozoite challenge, and sterile protection, as defined by the absence of detectable blood-stage parasites, was observed in the majority of the mice. In contrast, mice immunized with recombinant P. yoelii YM MSP-1 were not protected against a heterologous challenge with sporozoites from strain 265 BY of P. yoelii. The lack of protection may be explained by differences identified in the amino acid sequences of MSP-1 for the two strains. A recombinant protein containing the two EGF-like modules of MSP-1 from P. yoelii 265 BY was produced and used to immunize mice. These mice were protected against a homologous challenge with sporozoites of P. yoelii 265 BY. The results suggest that a recombinant MSP-1 has potential as a vaccine against malaria, but its efficacy may be limited by sequence polymorphism and selection of variants.
Collapse
Affiliation(s)
- L Rénia
- U313 INSERM, CHU Pitié-Salpêtrière, Paris, France.
| | | | | | | | | | | |
Collapse
|
21
|
Affiliation(s)
- A A Holder
- Division of Parasitology, National Institute for Medical Research, London, UK
| |
Collapse
|
22
|
|
23
|
Borre MB, Dziegiel M, Høgh B, Petersen E, Rieneck K, Riley E, Meis JF, Aikawa M, Nakamura K, Harada M. Primary structure and localization of a conserved immunogenic Plasmodium falciparum glutamate rich protein (GLURP) expressed in both the preerythrocytic and erythrocytic stages of the vertebrate life cycle. Mol Biochem Parasitol 1991; 49:119-31. [PMID: 1775153 DOI: 10.1016/0166-6851(91)90135-s] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A gene coding for a 220-kDa glutamate rich protein (GLURP), an exoantigen of Plasmodium falciparum, was isolated and its nucleotide sequence was determined. The deduced amino acid sequence contains 2 repeat regions. The sequence of one of these was shown to be conserved among geographically dispersed isolates, and a fusion protein containing that sequence was able to stimulate B- and T-cells. Antibodies against GLURP stained erythrocytic stages of the parasite as well as the hepatic stage as detected by electron microscopy.
Collapse
Affiliation(s)
- M B Borre
- Department of Infection-Immunology, Statens Seruminstitut, Copenhagen, Denmark
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Survival and antigenic profile of irradiated malarial sporozoites in infected liver cells. Infect Immun 1990; 58:2834-9. [PMID: 1974886 PMCID: PMC313575 DOI: 10.1128/iai.58.9.2834-2839.1990] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Exoerythrocytic (EE) stages of Plasmodium berghei derived from irradiated sporozoites were cultured in vitro in HepG2 cells. They synthesized several antigens, predominantly but not exclusively those expressed by normal early erythrocytic schizonts. After invasion, over half the intracellular sporozoites, both normal and irradiated, appeared to die. After 24 h, in marked contrast to the normal parasites, EE parasites derived from irradiated sporozoites continued to break open, shedding their antigens into the cytoplasm of the infected host cells. Increasing radiation dosage, which has previously been shown to reduce the ability of irradiated sporozoites to protect animals, correlated with reduced de novo antigen synthesis by EE parasites derived from irradiated sporozoites.
Collapse
|
25
|
Suhrbier A, Winger L, O'Dowd C, Hodivala K, Sinden RE. An antigen specific to the liver stage of rodent malaria recognized by a monoclonal antibody. Parasite Immunol 1990; 12:473-81. [PMID: 2255559 DOI: 10.1111/j.1365-3024.1990.tb00982.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Vaccines currently being evaluated against malaria are based on proteins derived from the blood, sporozoite and sexual stages. Antigens from the liver stage, which is now recognized as the major target of protective sporozoite induced immunity, have received comparatively little attention. This paper describes the generation of a monoclonal antibody (MoAb), which recognizes an antigen specific to the liver stage of the rodent malaria Plasmodium berghei. The antigen is expressed throughout liver stage development and appears to be localized to the parasitophorous vacuole membrane. The MoAb did not affect the growth of liver stages cultured in vitro nor could protection be demonstrated in vivo following passive transfer of the antibody.
Collapse
Affiliation(s)
- A Suhrbier
- Department of Pure and Applied Biology, Imperial College, London
| | | | | | | | | |
Collapse
|
26
|
Suhrbier A, Wiser MF, Winger L, Harte P, Newton MF, Hodivala KJ, Nicholas J, Sinden RE. Contrasts in antigen expression in the erythrocytic and exoerythrocytic stages of rodent malaria. Parasitology 1989; 99 Pt 2:165-70. [PMID: 2687775 DOI: 10.1017/s0031182000058595] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The time and site of expression of five antigens, recognized by monoclonal antibodies raised against blood-stage parasites, were studied in the exoerythrocytic stage of Plasmodium berghei using indirect immunofluorescent antibody staining. Two monoclonal antibodies (W 3.5, I 2.6), which stain the cytoplasm of infected erythrocytes, did not stain the cytoplasm of the infected liver cell but stained the parasite itself suggesting a difference in the antigenic architecture of the erythrocytic and exoerythrocytic parasites. Another antibody (17.6.1) revealed a further difference in the antigenic composition of the blood and liver-stage parasites being expressed almost exclusively in the former. Two others (C139 and 17.3.9) showed broadly similar patterns of expression in these two stages of the malarial life-cycle.
Collapse
Affiliation(s)
- A Suhrbier
- Department of Pure and Applied Biology, Imperial College, London
| | | | | | | | | | | | | | | |
Collapse
|