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Chia WN, Goh YS, Rénia L. Novel approaches to identify protective malaria vaccine candidates. Front Microbiol 2014; 5:586. [PMID: 25452745 PMCID: PMC4233905 DOI: 10.3389/fmicb.2014.00586] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/17/2014] [Indexed: 12/17/2022] Open
Abstract
Efforts to develop vaccines against malaria have been the focus of substantial research activities for decades. Several categories of candidate vaccines are currently being developed for protection against malaria, based on antigens corresponding to the pre-erythrocytic, blood stage, or sexual stages of the parasite. Long lasting sterile protection from Plasmodium falciparum sporozoite challenge has been observed in human following vaccination with whole parasite formulations, clearly demonstrating that a protective immune response targeting predominantly the pre-erythrocytic stages can develop against malaria. However, most of vaccine candidates currently being investigated, which are mostly subunits vaccines, have not been able to induce substantial (>50%) protection thus far. This is due to the fact that the antigens responsible for protection against the different parasite stages are still yet to be known and relevant correlates of protection have remained elusive. For a vaccine to be developed in a timely manner, novel approaches are required. In this article, we review the novel approaches that have been developed to identify the antigens for the development of an effective malaria vaccine.
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Affiliation(s)
- Wan Ni Chia
- Singapore Immunology Network, Agency for Science, Technology and Research Singapore, Singapore ; Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
| | - Yun Shan Goh
- Singapore Immunology Network, Agency for Science, Technology and Research Singapore, Singapore
| | - Laurent Rénia
- Singapore Immunology Network, Agency for Science, Technology and Research Singapore, Singapore ; Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore Singapore, Singapore
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Anders RF, Shi PT, Scanlon DB, Leach SJ, Coppel RL, Brown GV, Stahl HD, Kemp DJ. Antigenic repeat structures in proteins of Plasmodium falciparum. CIBA FOUNDATION SYMPOSIUM 2007; 119:164-83. [PMID: 2426051 DOI: 10.1002/9780470513286.ch10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The majority of malaria antigens that have been cloned contain short sequence repeats which encode antigenic epitopes that are naturally immunogenic. Synthetic peptides have been used to show that natural antibody responses to a strain-specific Plasmodium falciparum S antigen are largely directed against epitopes encoded in an 11-amino acid sequence that is repeated approximately 100 times in the molecule. A 16-amino acid peptide conjugated to bovine serum albumin induced antibodies specific for the S antigen of the homologous isolate. Synthetic peptides have also been used to confirm the natural immunogenicity of epitopes encoded within two blocks of related repeats in the Ring-infected Erythrocyte Surface Antigen (RESA). A 16-amino acid peptide, comprising four repeats of the tetrameric sequence EENV, induced antibodies reactive with the native molecule. Detailed analyses of these anti-peptide antisera indicate that short sequence repeats express more than one epitope, some of which may cross-react with other repeat structures.
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Richie T. High road, low road? Choices and challenges on the pathway to a malaria vaccine. Parasitology 2007; 133 Suppl:S113-44. [PMID: 17274843 DOI: 10.1017/s0031182006001843] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Malaria causes much physical and economic hardship in endemic countries with billions of people at risk. A vaccine would clearly benefit these countries, reducing the requirement for hospital care and the economic impact of infection. Successful immunization with irradiated sporozoites and the fact that repeated exposure to malaria induces partial immunity to infection and high levels of protection against the clinical manifestations, suggest that a vaccine is feasible. Numerous candidate antigens have been identified but the vaccine, which has been promised to be 'just round the corner' for many years, remains elusive. The factors contributing to this frustratingly slow progress are discussed including gaps in the knowledge of host/parasite biology, methods to induce potent cell-mediated immune responses, the difficulties associated with defining immune correlates of protection and antigen production and delivery. Finally, the use of attenuated organism vaccines is discussed.
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Affiliation(s)
- T Richie
- Malaria Program, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, Maryland 20910-7500, USA.
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Sowa MPK, Sharling L, Humphreys G, Cavanagh DR, Gregory WF, Fenn K, Creasey AM, Arnot DE. High throughput immuno-screening of cDNA expression libraries produced by in vitro recombination; exploring the Plasmodium falciparum proteome. Mol Biochem Parasitol 2004; 133:267-74. [PMID: 14698438 DOI: 10.1016/j.molbiopara.2003.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Improved Plasmodium falciparum cDNA expression libraries were constructed by combining mRNA oligo-capping with in vitro recombination and directional cloning of cDNA inserts into a plasmid vector that expresses sequences as thioredoxin fusion proteins. A novel procedure has also been developed for the rapid identification of seropositive clones on high-density filters, using direct labelling of P. falciparum immune immunoglobulin with fluorescein isothiocynate (FITC). This approach combines the advantages of recombination-assisted cDNA cloning with high throughput, non-radioactive serological screening of expression libraries. Production of replicate colony matrices allows the identification of antigens recognised by different pools with different specificities from residents of a malaria endemic region. Analyses of DNA sequences derived from sero-reactive colonies indicate that this is an effective method for producing recombinant proteins that react with antibodies from malaria-exposed individuals. This approach permits the systematic construction of a database of antigenic proteins recognised by sera from malaria-exposed individuals.
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Affiliation(s)
- M P Kordai Sowa
- Institute of Cell, Animal and Population Biology, Ashworth Laboratories, Kings' Buildings, University of Edinburgh, West Mains Road, Edinburgh, Scotland, UK.
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Howard RF, Jensen JB, Franklin HL. Reactivity profile of human anti-82-kilodalton rhoptry protein antibodies generated during natural infection with Plasmodium falciparum. Infect Immun 1993; 61:2960-5. [PMID: 7685740 PMCID: PMC280945 DOI: 10.1128/iai.61.7.2960-2965.1993] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Immunization of monkeys with the 82-kDa rhoptry protein (p82) of Plasmodium falciparum can protect them against a lethal blood stage challenge, and monoclonal antibodies to p82 inhibit parasite growth in vitro. The role that a p82-specific immune response might play in human immunity to the parasite is not known. To determine to what extent humans produce antibodies to p82 following infection with P. falciparum, sera from individuals believed to be hyperimmune, semi-immune, or never infected with the parasite were examined. Portions of the p82 gene were expressed separately as fusion proteins and used on immunoblots to test for antibodies to the recombinant proteins. All but 1 of the 30 immune sera possessed antibodies to p82, while nonimmune sera produced, at best, only a marginal signal to the fusion proteins. The signal intensity produced with the human immune sera depended on the region of p82 being assayed, with the N-terminal 37% of p82 producing stronger signals than more C-terminal parts of p82. This N-terminal domain contains a tandem octapeptide repeat (consensus KSSSPSXT/V) of the structure (repeat)2-Q-T-S-G-S/L-(repeat)3. It is shown here that the sequence of this repetitive motif is conserved among four parasite isolates at both the nucleotide and amino acid levels; the five-residue repeat interruption peptide QTSGS/L separating the two sets of repeats contains the only amino acid substitution (Ser or Leu) detected in this region to date. Despite their conservation of structure, the repeats do not appear to be the only epitope recognized by the human antibodies, since sera which recognize the N-terminal fusion protein containing the repeats also bind a related protein after truncation and removal of the repeats. These results indicate that the structurally conserved p82 molecule contains multiple B-cell epitopes and is likely to be immunogenic in most individuals during natural infections with P. falciparum. These observations are consistent with the idea that antibodies to p82 generated during parasite infection have a role in the development of immunity to the organism.
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Affiliation(s)
- R F Howard
- Seattle Biomedical Research Institute, Washington 98109
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Sartorius C, Franklin RM. Hybridization arrest of cell-free translation of the malarial dihydrofolate reductase/thymidylate synthase mRNA by anti-sense oligodeoxyribonucleotides. Nucleic Acids Res 1991; 19:1613-8. [PMID: 2027768 PMCID: PMC333923 DOI: 10.1093/nar/19.7.1613] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In order to inhibit the in vitro translation of Plasmodium falciparum mRNA coding for the bifunctional enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS), oligodeoxynucleotides (ODNs) were directed against the translation initiation site or a site in the TS-coding region. In both cases considerable hybridization arrest, i.e. greater than 50% inhibition, was only achieved if the lengths of the ODNs to the two regions were 30 and 39 nucleotides, respectively, or longer. The ODN with the highest efficiency was a 49-mer directed against the TS-coding region (OTS49); 45 microM was sufficient to inhibit the expression of DHFR-TS by almost 90%. In this case the synthesis of DHFR-TS was interrupted at the binding site of OTS49 by a RNase H-independent mechanism. The resulting polypeptide was smaller (55 kDa) than one subunit of the native protein (71 kDa) and lacked TS activity.
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Affiliation(s)
- C Sartorius
- Biocenter, Department Structural Biology, Basel, Switzerland
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Kemp DJ, Cowman AF, Walliker D. Genetic diversity in Plasmodium falciparum. ADVANCES IN PARASITOLOGY 1990; 29:75-149. [PMID: 2181830 DOI: 10.1016/s0065-308x(08)60105-0] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- D J Kemp
- Walter and Eliza Hall Institute of Medical Research, Victoria, Australia
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Knight M, Kelly C, Rodrigues V, Yi X, Wamachi A, Smithers SR, Simpson AJ. A cDNA clone encoding part of the major 25,000-dalton surface membrane antigen of adult Schistosoma mansoni. Parasitol Res 1989; 75:280-6. [PMID: 2649880 DOI: 10.1007/bf00931812] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Immunoscreening of an adult Schistosoma mansoni cDNA expression library, using antibodies raised against purified adult worm tegumental surface membranes, identified a recombinant clone containing a 141-bp insert. Antibodies raised against the recombinant antigen bound specifically to the tegument of adult worms and immunoprecipitated the major 25,000-dalton surface membrane antigen as well as a 22,000-dalton nascent polypeptide generated by cell-free translation of adult S. mansoni mRNA. The mature 25,000-dalton antigen was found to be precipitated by antibodies from infected mice, rats and humans.
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Affiliation(s)
- M Knight
- Division of Parasitology, National Institute for Medical Research, Mill Hill, London, UK
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Richman SJ, Reese RT. Immunologic modeling of a 75-kDa malarial protein with carrier-free synthetic peptides. Proc Natl Acad Sci U S A 1988; 85:1662-6. [PMID: 2449696 PMCID: PMC279834 DOI: 10.1073/pnas.85.5.1662] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A protein of 75 kDa is produced in large quantities by the human malarial parasite Plasmodium falciparum and is present on the surface of the merozoite, whose function is to infect erythrocytes. Based on nucleotide sequence coding for 40% of this protein, two nonoverlapping model peptides 13 and 19 residues long were synthesized, coupled to a keyhole limpet hemocyanin carrier, and used to immunize rabbits. Although both antisera had high titers of anti-peptide antibodies, only that raised against the 13-residue peptide showed good reactivity against the original protein. Although the 19-mer adopted the helical secondary structure predicted for the corresponding protein region, antisera against this peptide reacted with the native protein weakly or not at all. Concluding that the poor anti-protein reactivity was due to modification of lysine-containing epitopes by glutaraldehyde conjugation, we used a carrier-free 28-residue peptide presented as a 56-residue disulfide-bonded dimer to model the same region. This peptide, in contrast to the conjugated 19-mer, stimulated the production of IgG antibodies that reacted at high dilution with the authentic protein in immunoblots, ELISA, and radioimmunoprecipitation assays. These data indicate that large carrier-free peptides may be successfully used as immunogens. In addition, our results show that this strategy may greatly improve the ability of conjugation-sensitive peptides to stimulate antibodies reactive with the original protein and therefore has substantial practical application.
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Trager W. The cultivation of Plasmodium falciparum: applications in basic and applied research on malaria. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 1987; 81:511-29. [PMID: 3331241 DOI: 10.1080/00034983.1987.11812153] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- W Trager
- Rockefeller University, New York, New York 10021
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Stahl HD, Bianco AE, Crewther PE, Burkot T, Coppel RL, Brown GV, Anders RF, Kemp DJ. An asparagine-rich protein from blood stages of Plasmodium falciparum shares determinants with sporozoites. Nucleic Acids Res 1986; 14:3089-102. [PMID: 2421257 PMCID: PMC339723 DOI: 10.1093/nar/14.7.3089] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We describe a cDNA clone derived from mRNA of asexual blood-stages of the malaria parasite Plasmodium falciparum. This clone, designated Ag319, expresses a P.falciparum antigen fused to beta-galactosidase in Escherichia coli. Human antibodies from Papua New Guinea were affinity-purified by adsorption to extracts of Ag319 immobilized on CNBr-Sepharose. The antibodies reacted predominantly with P. falciparum polypeptides of Mr 220,000 and 160,000, and a number of ill-defined lower molecular weight species. Antibodies reacted in indirect immunofluorescence with all asexual blood-stages although the antigen appeared to be most abundance in the schizont. Surprizingly the antibodies also reacted with sporozoites. The amino acid sequence predicted from the complete nucleotide sequence of this clone is remarkable because 40% of the residues are Asn, and so the antigen has been termed the Asparagine-Rich Protein (ARP). Like other P. falciparum antigens, ARP contains tandemly repetitive sequences, based on the tetrapeptide Asn-Asn-Asn-Met and we have confirmed that these represent natural epitopes by reaction of the corresponding synthetic peptides with human antibodies. Surprisingly, ARP is also rich in Asn outside the tandem repeats.
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12
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Kemp DJ, Coppel RL, Stahl HD, Bianco AE, Corcoran LM, McIntyre P, Langford CJ, Favaloro JM, Crewther PE, Brown GV. The Wellcome Trust lecture. Genes for antigens of Plasmodium falciparum. Parasitology 1986; 92 Suppl:S83-108. [PMID: 2423947 DOI: 10.1017/s0031182000085711] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Sporozoites ofP. falciparumand other Plasmodia appear to be fairly simple antigenically, in that there is a dominant antigen, the circumsporozoite (CS) protein that forms the sporozoite surface coat (Potocnjak, Yoshida, Nussenzweig & Nussensweig, 1980; Santoroet al.1983). Consequently, the CS protein and the gene encoding it have now been studied in considerable detail (Elliset al.1983; Godsonet al.1983; Ozakiet al.1983; Dameet al.1984; Eneaet al.1984). In contrast to sporozoites, the asexual blood stagesof P. falciparumare antigenically complex. Two-dimensional gel analyses of immunoprecipitated, biosynthetically labelled antigens indicate that repeated infection withP. falciparumresults in the synthesis of antibodies against a large number of distinct antigens (Perrin & Dayal, 1982; Brownet al.1981, 1983). In further contrast to the sporozoite, the asexual blood stages of differentP. falciparumisolates exhibit a high degree of antigenic heterogeneity (Brownet al.1983; Hallet al.1983; McBride, Walliker & Morgan, 1982). Much of this antigenic diversity is no doubt due to allelic differences but clonal populations of parasites may also have the capacity to undergo antigenic variation (Hommel, David & Oligino, 1983).
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Selkirk ME, Denham DA, Partono F, Sutanto I, Maizels RM. Molecular characterization of antigens of lymphatic filarial parasites. Parasitology 1986; 92 Suppl:S15-38. [PMID: 2423945 DOI: 10.1017/s003118200008567x] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Three species of filarial worms,Wuchereria bancrofti, Brugia malayiandBrugia timori, are the causative agents of lymphatic filariasis in man, defined by the characteristic tropism of adult worms of each species for the afferent lymphatics. Reproductive activity leads to the release of large numbers of microfilariae, which circulate in the vascular system, and upon ingestion by an appropriate mosquito vector, develop through to infective third-stage larvae (L3) within 10–14 days. After a subsequent bloodmeal, the infective larvae enter the definitive host via the wound and mature to the adult stage over several months, involving two moults, during which the entire nematode exoskeleton (cuticle) is replaced.
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MESH Headings
- Animals
- Antigens, Helminth/analysis
- Antigens, Helminth/genetics
- Antigens, Helminth/immunology
- Brugia/genetics
- Brugia/immunology
- Cats
- Cloning, Molecular
- Cross Reactions
- DNA/genetics
- Disease Models, Animal
- Electrophoresis, Polyacrylamide Gel
- Elephantiasis, Filarial/immunology
- Epitopes
- Female
- Filariasis/diagnosis
- Filariasis/immunology
- Gerbillinae
- Humans
- Immunity, Active
- Immunity, Innate
- Immunity, Maternally-Acquired
- Male
- RNA/genetics
- Sex Factors
- Urea/analogs & derivatives
- Wuchereria/immunology
- Wuchereria bancrofti/genetics
- Wuchereria bancrofti/immunology
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Stanley HA, Reese RT. Monkey-derived monoclonal antibodies against Plasmodium falciparum. Proc Natl Acad Sci U S A 1985; 82:6272-5. [PMID: 3898084 PMCID: PMC391035 DOI: 10.1073/pnas.82.18.6272] [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: 01/07/2023] Open
Abstract
A system has been developed that allows efficient production of monkey monoclonal antibodies from owl monkeys. Splenocytes or peripheral blood lymphocytes from monkeys immune to the human malarial parasite, Plasmodium falciparum, were fused with P3X63 Ag8.653 mouse myelomas. The resulting hybridomas were screened by an indirect fluorescent antibody test for the production of monkey monoclonal antibodies (mAb) reactive with P. falciparum. Most of the mAb reacted with the P. falciparum merozoites and immunoprecipitated a parasite-derived glycoprotein having a relative molecular weight of 185,000. These mAb gave a minimum of five different immunoprecipitation patterns, thus demonstrating that a large number of polypeptides obtained when parasitized erythrocytes are solubilized share epitopes with this large glycoprotein. In addition, mAb were obtained that reacted with antigens associated with the infected erythrocyte membrane. One of these mAb bound a Mr 95,000 antigen.
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Ravetch JV, Young J, Poste G. Molecular Genetic Strategies for the Development of Anti-Malarial Vaccines. ACTA ACUST UNITED AC 1985. [DOI: 10.1038/nbt0885-729] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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