In vitro phagocytosis inhibition assay for the screening of potential candidate antigens for sub-unit vaccines against the asexual blood stage of Plasmodium falciparum

Gysin, Jürg; Gavoille, Stephane; Mattei, Denise; Scherf, Arthur; Bonnefoy, Serge; Mercereau‐Puijalon, Odile; Feldmann, Thomas; Müller‐Hill, Benno; Silva, Luiz Pereira da

doi:10.1016/0022-1759(93)90159-5

Cited by 36 publications

(14 citation statements)

References 35 publications

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“…Asparagine-rich motifs in proteins are targets of opsonizing antibodies that promote phagocytosis of parasites by immune cells (3,4,15). The abundance of the asparagine residue (6.87%) and the recognition of the recombinant PkSPATR by immune sera from multiple P. knowlesi infections and drugcured rhesus monkeys in enzyme-linked immunosorbent assay indicate that PkSPATR could be a target of opsonizing antibodies.…”

Section: Discussionmentioning

confidence: 99%

Identification, Cloning, Expression, and Characterization of the Gene for Plasmodium knowlesi Surface Protein Containing an Altered Thrombospondin Repeat Domain

et al. 2005

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Proteins present on the surface of malaria parasites that participate in the process of invasion and adhesion to host cells are considered attractive vaccine targets. Aided by the availability of the partially completed genome sequence of the simian malaria parasite Plasmodium knowlesi, we have identified a 786-bp DNA sequence that encodes a 262-amino-acid-long protein, containing an altered version of the thrombospondin type I repeat domain (SPATR). Thrombospondin type 1 repeat domains participate in biologically diverse functions, such as cell attachment, mobility, proliferation, and extracellular protease activities. The SPATR from P. knowlesi (PkSPATR) shares 61% and 58% sequence identity with its Plasmodium falciparum and Plasmodium yoelii orthologs, respectively. By immunofluorescence analysis, we determined that PkSPATR is a multistage antigen that is expressed on the surface of P. knowlesi sporozoite and erythrocytic stage parasites. Recombinant PkSPATR produced in Escherichia coli binds to a human hepatoma cell line, HepG2, suggesting that PkSPATR is a parasite ligand that could be involved in sporozoite invasion of liver cells. Furthermore, recombinant PkSPATR reacted with pooled sera from P. knowlesi-infected rhesus monkeys, indicating that native PkSPATR is immunogenic during infection. Further efficacy evaluation studies in the P. knowlesi-rhesus monkey sporozoite challenge model will help to decide whether the SPATR molecule should be developed as a vaccine against human malarias.An effective vaccine that reduces malaria-related mortality and morbidity would indeed alleviate the suffering of millions of people around the world (17). The onset and progression of malaria infection require a complex sequence of recognition, adhesion, and invasion events between the parasite and host cells. To accomplish this, the parasite expresses a multitude of proteins on its surface that serve as ligands that interact with the receptors present on the host cells. For example, circumsporozoite protein and thrombospondin-related anonymous protein (two sporozoite-stage proteins) participate in the binding of malaria sporozoites to liver cells (6, 30). In the erythrocytic-stage cycle, erythrocyte-binding antigen 175 is recognized as a merozoite ligand that binds to glycophorin A on erythrocytes to initiate the process of merozoite invasion (33). Likewise, the products of the var genes expressed on the surface of infected erythrocytes facilitate the adherence of mature forms of parasites to deep venules of endothelial cells and thus shield them from clearance by the host immune system.The standard steps in preclinical vaccine development prior to phase I clinical trials in humans are antigen identification, its biochemical/biological characterization, and efficacy evaluation in animal models. For malaria, animal studies are generally performed using pertinent orthologs of Plasmodium falciparum (the most lethal form of human malaria) in the mouse (Plasmodium yoelii/Plasmodium berghei) and monkey (Plasmodium knowlesi) mo...

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Section: Discussionmentioning

confidence: 99%

Identification, Cloning, Expression, and Characterization of the Gene for Plasmodium knowlesi Surface Protein Containing an Altered Thrombospondin Repeat Domain

et al. 2005

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“…28 In addition, we cannot exclude the possibility that the recombinant proteins do not optimally mimic the native parasite antigens. However, the fact that the R23 and PfEB200 proteins competed efficiently with IRBC in the in vitro opsonization assay 7 indicates that some critical native epitopes are expressed by the recombinant antigens.…”

Section: Discussionmentioning

confidence: 99%

“…7 This identified the R23 and PfEB200 antigens as targets of opsonizing antibodies. R23 derives from the central domain of the R45 antigen: it consists of 11 copies of a 6-amino-acid motif.…”

Section: Introductionmentioning

confidence: 99%

Seasonal fluctuation of antibody levels to Plasmodium falciparum parasitized red blood cell-associated antigens in two Senegalese villages with different transmission conditions.

Perraut¹,

Mercereau‐Puijalon²,

Diouf³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

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Abstract. The recombinant R23, PfEB200, and GST-5 antigens derive from conserved antigens associated with the Plasmodium falciparum-infected erythrocyte membrane. They were identified as targets of protective antibodies in the Saimiri sciureus model. We have assessed here the humoral response to these antigens in humans. Crosssectional surveys were conducted in two Senegalese villages with different levels of endemicity. The prevalence of specific IgG and IgM was similar and influenced by age in both localities. The anti-R23 antibodies decreased after the rainy season, particularly in the children less than ten years old. The anti-PfEB200 response did not show significant seasonal variation. The anti-GST-5 response increased in both the less-than 10-year-old and the greaterthan 10-year-old groups after the rainy season in Dielmo, but only in the Ndiop villagers who were more than 10-years-old. Thus, antigen-specific seasonal variations of antibody levels were influenced differently by age in both villages. The isotype distribution was antigen-specific and differed for both seasons.

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“…Antibodies to Pf332 repeats, raised in animals or affinity purified from human serum, inhibit in vitro parasite growth. 10,11 Additionally, antibodies reactive with the Pf332-derived recombinant fragment EB200 mediate cellular elimination of parasitized red blood cells by acting as opsonins, 12 and immunization of Saimiri monkeys with recombinant EB200 induced opsonizing antibodies. 13 An essential feature of a malaria vaccine candidate antigen is the capacity to elicit relevant T cell responses, a prerequisite for efficient B cell responses.…”

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confidence: 99%

Human immune responses to the highly repetitive Plasmodium falciparum antigen Pf332.

Kulane

Siddique²,

Sarthou³

et al. 1999

The American Journal of Tropical Medicine and Hygiene

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Abstract. The B and T cell responses to EB200, a repetitive part of the Plasmodium falciparum antigen Pf332, were examined in malaria-exposed Senegalese adults. Most donors had high levels of antibodies to recombinant EB200 and 17 overlapping peptides spanning EB200. Taking proliferation and/or cytokine (interferon-␥ and interleukin-4) production as a measure of T cell activation, eight of the EB200-derived peptides induced responses in Ͼ 40% of the donors tested. There was no general association between the different types of T cell responses measured, emphasizing the importance of including multiple parameters when analyzing T cell responses and suggesting that EB200 induces functionally distinct T cell responses. The most efficient peptide for induction of proliferative responses was one previously shown to induce T cell responses in five different H-2 congenic mouse strains primed with EB200, suggesting that this is a universal T cell epitope. The presence of multiple B and T cell epitopes in EB200, widely recognized by humans, is important since EB200 has been shown to elicit protective antibody responses in monkeys and may be considered for inclusion in malaria subunit vaccines.The Plasmodium falciparum antigen Pf332 is of potential interest for inclusion in a subunit vaccine against the malaria parasite.

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In vitro phagocytosis inhibition assay for the screening of potential candidate antigens for sub-unit vaccines against the asexual blood stage of Plasmodium falciparum

Cited by 36 publications

References 35 publications

Identification, Cloning, Expression, and Characterization of the Gene for Plasmodium knowlesi Surface Protein Containing an Altered Thrombospondin Repeat Domain

Identification, Cloning, Expression, and Characterization of the Gene for Plasmodium knowlesi Surface Protein Containing an Altered Thrombospondin Repeat Domain

Seasonal fluctuation of antibody levels to Plasmodium falciparum parasitized red blood cell-associated antigens in two Senegalese villages with different transmission conditions.

Human immune responses to the highly repetitive Plasmodium falciparum antigen Pf332.

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