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Zofou D, Nyasa RB, Nsagha DS, Ntie-Kang F, Meriki HD, Assob JCN, Kuete V. Control of malaria and other vector-borne protozoan diseases in the tropics: enduring challenges despite considerable progress and achievements. Infect Dis Poverty 2014; 3:1. [PMID: 24401663 PMCID: PMC3895778 DOI: 10.1186/2049-9957-3-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 01/02/2014] [Indexed: 01/22/2023] Open
Abstract
Vector-borne protozoan diseases represent a serious public health challenge, especially in the tropics where poverty together with vector-favorable climates are the aggravating factors. Each of the various strategies currently employed to face these scourges is seriously inadequate. Despite enormous efforts, vaccines-which represent the ideal weapon against these parasitic diseases-are yet to be sufficiently developed and implemented. Chemotherapy and vector control are therefore the sole effective attempts to minimize the disease burden. Nowadays, both strategies are also highly challenged by the phenomenon of drug and insecticide resistance, which affects virtually all interventions currently used. The recently growing support from international organizations and governments of some endemic countries is warmly welcome, and should be optimally exploited in the various approaches to drug and insecticide research and development to overcome the burden of these prevalent diseases, especially malaria, leishmaniasis, Human African Trypanosomiasis (HAT), and Chagas disease.
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Affiliation(s)
- Denis Zofou
- Biotechnology Unit, Faculty of Science, University of Buea, P,O, Box 63, Buea, South West Region, Cameroon.
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2
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Bastos MS, da Silva-Nunes M, Malafronte RS, Hoffmann EHE, Wunderlich G, Moraes SL, Ferreira MU. Antigenic polymorphism and naturally acquired antibodies to Plasmodium vivax merozoite surface protein 1 in rural Amazonians. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2007; 14:1249-59. [PMID: 17699838 PMCID: PMC2168105 DOI: 10.1128/cvi.00243-07] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Merozoite surface protein 1 of Plasmodium vivax (PvMSP-1), a major target for malaria vaccine development, contains six highly polymorphic domains interspersed with conserved sequences. Although there is evidence that the sequence divergence in PvMSP-1 has been maintained over 5 million years by balanced selection exerted by the host's acquired immunity, the variant specificity of naturally acquired antibodies to PvMSP-1 remains poorly investigated. Here, we show that 15 recombinant proteins corresponding to PvMSP-1 variants commonly found in local parasites were poorly recognized by 376 noninfected subjects aged 5 to 90 years exposed to malaria in rural Amazonia; less than one-third of them had detectable immunoglobulin G (IgG) antibodies to at least one variant of blocks 2, 6, and 10 that were expressed, although 54.3% recognized the invariant 19-kDa C-terminal domain PvMSP-1(19). Although the proportion of responders to PvMSP-1 variants increased substantially during subsequent acute P. vivax infections, the specificity of IgG antibodies did not necessarily match the PvMSP-1 variant(s) found in infecting parasites. We discuss the relative contribution of antigenic polymorphism, poor immunogenicity, and original antigenic sin (the skew in the specificity of antibodies elicited by exposure to new antigenic variants due to preexisting variant-specific responses) to the observed patterns of antibody recognition of PvMSP-1. We suggest that antibody responses to the repertoire of variable domains of PvMSP-1 to which subjects are continuously exposed are elicited only after several repeated infections and may require frequent boosting, with clear implications for the development of PvMSP-1-based subunit vaccines.
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MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Amino Acid Sequence
- Animals
- Antibodies, Protozoan/biosynthesis
- Antibodies, Protozoan/blood
- Antigenic Variation/genetics
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Brazil
- Child
- Child, Preschool
- Cohort Studies
- Female
- Genetic Variation
- Humans
- Immunity, Innate/genetics
- Infant
- Infant, Newborn
- Male
- Merozoite Surface Protein 1/genetics
- Merozoite Surface Protein 1/immunology
- Middle Aged
- Molecular Sequence Data
- Plasmodium vivax/genetics
- Plasmodium vivax/immunology
- Polymorphism, Genetic
- Protein Structure, Tertiary/genetics
- Rural Population
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Affiliation(s)
- Melissa S Bastos
- Laboratories of Immunoepidemology, Institute of Tropical Medicine of São Paulo, University of São Paulo, 05403-000 São Paulo, Brazil
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3
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Garraud O, Relave J, Flori P, Perraut R. [Post-transfusion malaria: is the risk irreconciliable with biological silence?]. Transfus Clin Biol 2004; 11:87-94. [PMID: 15120105 DOI: 10.1016/j.tracli.2004.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2004] [Accepted: 02/25/2004] [Indexed: 10/26/2022]
Abstract
Despite the relatively high frequency of imported malaria in metropolitan France, the transmission of malaria by transfusion is exceptional. The screening of donations to determine those at risk is performed by an interview, and by the testing of serology for defined groups of donors. However, the exclusion of a candidate 'at risk' as a blood donor, by a pre-donation interview, is not completely mastered and the discrimination by biological examination lacks sensitivity, as much for methodological reasons as for reasons linked to the complex parasitic pathogenic agent (Plasmodium ssp.), as for the specific host defence system. The risk of introducing an unsafe-potentially dangerous (transfusion-transmitted malaria is often lethal)-element into the transfusional circuit is not completely covered. Is serology testing the most adequate test to avoid the risk of infected donations, in particular by Plasmodium falciparum; what are the alternatives and what will be the eventual added-costs of the biological qualification of such donations? The transfusional risk linked to Plasmodium seems, however, to be reduced to a minimum, concerning the circulation of plasma, which could represent an alternative for donors at real risk (rare) and those with a supposed risk (relatively numerous).
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Affiliation(s)
- O Garraud
- EFS Auvergne-Loire, 25, boulevard Pasteur, 42000 Saint-Etienne cedex 2, France.
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4
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Carvalho LJM, Daniel-Ribeiro CT, Goto H. Malaria vaccine: candidate antigens, mechanisms, constraints and prospects. Scand J Immunol 2002; 56:327-43. [PMID: 12234254 DOI: 10.1046/j.1365-3083.2002.01160.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
More than 30 years after the first report of successful vaccination against malaria using radiation-attenuated sporozoites, an effective malaria vaccine is not yet available. However, field and experimental data indicate that it can be developed. An astonishing amount of data has accumulated concerning parasite biology, host-parasite interactions, immunity and escape mechanisms, targets and modulators of immune responses. Nevertheless, so far this knowledge has not been enough to make us understand how to properly manipulate the whole system to build an effective vaccine. In this article, we describe candidate antigens, mechanisms, targets and trials performed with potential malaria vaccines and discuss the approaches, in vivo and in vitro models, constraints and how technologies such as DNA vaccination, genomics/proteomics and reverse immunogenetics are providing exciting results and opening new doors to make malaria vaccine a reality.
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Affiliation(s)
- L J M Carvalho
- Department of Immunology, WHO Collaborating Centre for Research and Training in the Immunology of Parasitic Diseases, Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brazil.
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Rao KVN, He YX, Ramaswamy K. Suppression of cutaneous inflammation by intradermal gene delivery. Gene Ther 2002; 9:38-45. [PMID: 11850721 DOI: 10.1038/sj.gt.3301622] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2001] [Accepted: 09/28/2001] [Indexed: 11/08/2022]
Abstract
Biological effects of in vivo transfection of a potential anti-inflammatory gene, designated Sm16, cloned from the human parasite Schistosoma mansoni were analyzed in these studies. A single intradermal injection of a full-length cDNA of Sm16 resulted in the expression of Sm16 in the epidermis, dermis, skin migratory cells and skin-draining lymph nodes of mice for up to 7 days. Subsequently the anti-inflammatory effect of this gene expression was evaluated by inducing an inflammatory response in the skin of mice. These studies showed that Sm16 gene delivery resulted in a significant suppression of cutaneous inflammation as shown by a reduction in cutaneous edema, decrease in neutrophil infiltration, suppression of pro-inflammatory cytokine expression and down-regulation of ICAM-1 expression in the skin inflammatory site. Cells collected from the skin-draining lymph nodes showed reduced proliferation to mitogen. Multiple intradermal injection of Sm16 cDNA failed to induce any antibody response in mice for up to 8 weeks after initial injection. These findings suggest a potential for developing Sm16 gene delivery as a therapeutic agent for treating inflammatory skin disorders.
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Affiliation(s)
- K V N Rao
- Department of Biomedical Sciences, College of Medicine, University of Illinois, Rockford, IL 61107, USA
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6
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Galinski MR, Ingravallo P, Corredor-Medina C, Al-Khedery B, Povoa M, Barnwell JW. Plasmodium vivax merozoite surface proteins-3beta and-3gamma share structural similarities with P. vivax merozoite surface protein-3alpha and define a new gene family. Mol Biochem Parasitol 2001; 115:41-53. [PMID: 11377738 DOI: 10.1016/s0166-6851(01)00267-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The genes encoding two merozoite surface proteins of Plasmodium vivax that are related to PvMSP3 [1] are reported. One of these genes was identified within P. vivax lambdagt11 clone 5.4, which was selected by immunoscreening with a Saimiri monkey antiserum. The insert DNA of this clone was used as a probe to isolate the complete gene from a P. vivax lambdaDASH genomic (g) DNA library. Antibodies to recombinant 5.4 and subsequent fusion proteins produce a pattern of circumferential surface fluorescence by indirect immunofluorescence assays (IFA) on segmented schizonts and free intact merozoites, and recognize a 125 kDa protein via western immunoblots. The gene, however, encodes a protein with a calculated size of 75677 Da, and 3' and 5' RACE analyses were employed to confirm the size of the gene and its coding region. The second related P. vivax gene was isolated by hybridization of a fragment of an orthologous P. knowlesi gene. The encoded proteins of all three related P. vivax genes have putative signal peptides, large central domains that contain >20% alanine residues bound by charged regions, are predicted to form alpha-helices with heptad repeat coiled-coil structures, and do not have a hydrophobic region that could anchor them to the surface of the merozoite. Although the overall identity in amino acid alignment among the three encoded proteins is low (<40%), the shared predicted structural features and motifs indicate that they are members of an intra-species family, which we are designating as the PvMSP-3 family with the reported members being Pvmsp-3alpha, Pvmsp-3beta, and Pvmsp-3gamma. We further demonstrate that this family also includes related proteins from P. knowlesi and P. falciparum.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Antigens, Protozoan/metabolism
- Base Sequence
- Blotting, Western
- DNA, Protozoan/analysis
- DNA, Protozoan/genetics
- Escherichia coli/genetics
- Escherichia coli/immunology
- Escherichia coli/metabolism
- Fluorescent Antibody Technique
- Genes, Protozoan
- Humans
- Malaria, Vivax/parasitology
- Molecular Sequence Data
- Plasmodium vivax/genetics
- Plasmodium vivax/growth & development
- Plasmodium vivax/metabolism
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Protozoan Proteins/metabolism
- Rabbits
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Recombinant Fusion Proteins/metabolism
- Saimiri
- Sequence Analysis, DNA
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Affiliation(s)
- M R Galinski
- Emory University, Department of Medicine, Emory Vaccine Research Center, Yerkes Primate Research Center, 954 Gatewood Road, 30329, Atlanta, GA, USA.
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7
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Yang HM. Malaria transmission model for different levels of acquired immunity and temperature-dependent parameters (vector). Rev Saude Publica 2000; 34:223-31. [PMID: 10920443 DOI: 10.1590/s0034-89102000000300003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE Describe the overall transmission of malaria through a compartmental model, considering the human host and mosquito vector. METHODS A mathematical model was developed based on the following parameters: human host immunity, assuming the existence of acquired immunity and immunological memory, which boosts the protective response upon reinfection; mosquito vector, taking into account that the average period of development from egg to adult mosquito and the extrinsic incubation period of parasites (transformation of infected but non-infectious mosquitoes into infectious mosquitoes) are dependent on the ambient temperature. RESULTS The steady state equilibrium values obtained with the model allowed the calculation of the basic reproduction ratio in terms of the model's parameters. CONCLUSIONS The model allowed the calculation of the basic reproduction ratio, one of the most important epidemiological variables.
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Affiliation(s)
- H M Yang
- Departamento de Matemática Aplicada do Instituto de Matemática, Estatística e Ciência da Computação, Universidade Estadual de Campinas. Campinas, SP, Brasil.
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Garraud O, Diouf A, Nguer CM, Dieye A, Longacre S, Kaslow DC, Holder AA, Tall A, Molez JF, Perraut R, Mercereau-Puijalon O. Different Plasmodium falciparum recombinant MSP1(19) antigens differ in their capacities to stimulate in vitro peripheral blood T lymphocytes in individuals from various endemic areas. Scand J Immunol 1999; 49:431-40. [PMID: 10219771 DOI: 10.1046/j.1365-3083.1999.00511.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study reports on T-cell proliferative responses to the 19-kDa C-terminal domain of the Plasmodium falciparum merozoite surface protein (MSP1(19)). Three different recombinant proteins were used: an Escherichia coli product expressing the first EGF-like domain and Saccharomyces cerevisiae and baculovirus/insect-cell-produced proteins containing both EGF-like domains, the latter protein being produced with or without N-glycosylation. Cell donors were P. falciparum-immune adults with no recent history of clinical malaria and recruited from three Senegalese settings with different epidemiological parasite transmission. Each mononuclear-blood-cell preparation was stimulated with a range of concentrations of the three proteins. Most subjects' mononuclear cells were reactive to at least one protein, but significant differences in lymphoproliferation were seen between the settings and within individual cultures depending on the protein source and concentration. Importantly, lymphoproliferation indices correlated inversely with the intensity of P. falciparum malaria transmission. When purified T lymphocytes were cultured in the presence of MSP1(19) plus autologous monocytes, B lymphocytes or a proposed CD1+ dendritic-cell population as costimulatory cells, significant differences were observed depending on the individual's previous exposure to parasites. This study shows that the stimulation of lymphocyte proliferation in vitro with MSP1(19) depends on several factors, including epidemiological conditions and protein preparations.
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Affiliation(s)
- O Garraud
- Unité d'Immunologie, Institut Pasteur, Dakar, Sénégal
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9
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Malaria ? Biologische Aspekte einer f�r den Menschen bedeutsamen Infektionskrankheit. Naturwissenschaften 1996. [DOI: 10.1007/bf01142002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Bonnefoy S, Guillotte M, Langsley G, Mercereau-Puijalon O. Plasmodium falciparum: Characterization of gene R45 encoding a trophozoite antigen containing a central block of six amino acid repeats. Exp Parasitol 1992; 74:441-51. [PMID: 1350536 DOI: 10.1016/0014-4894(92)90206-p] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We describe here an antigen, called R45, expressed by the young trophozoites of Plasmodium falciparum. This antigen contains a block of tandem repeats of six amino acids which are recognized by sera from humans living in endemic areas. The R45 gene is located on chromosome 3. It is present in all strains examined and shows limited size polymorphism. The C-terminal unique region of the protein shows a strong homology with the catalytic domain of the serine protein kinases. Interestingly, the central repeats contain a large number of putative phosphorylation sites. The implications of these features are discussed.
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Affiliation(s)
- S Bonnefoy
- Unité de Parasitologie Expérimentale, Institut Pasteur, Paris, France
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