Characterisation of the binding sites of monoclonal antibodies reacting with the Plasmodium falciparum rhoptry protein RhopH3

Doury, J. C.; Goasdoue, Jean-Louis; Tolou, Hugues; Martelloni, Maryse; Bonnefoy, Serge; Mercereau‐Puijalon, Odile

doi:10.1016/s0166-6851(96)02819-8

Cited by 16 publications

(16 citation statements)

References 35 publications

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“…These results suggest that Toxoplasma N-glycans are composed of a mix of Man 5 GlcNAc 2 and Man 9 GlcNAc 2 , as recently proposed (19). (14,30,51). Alternatively, GFP is targeted to apicoplasts (ACP leader -GFP) and the parasitophorous vacuole (ACP signal -GFP) (55).…”

Section: Fig 4 Deconvolving Micrographs Of Plasmodium-infected Rbcssupporting

confidence: 70%

“…GSL-II labeling overlaps best with the binding of antibodies to rhoptry protein 3 (anti-RhopH3) (Fig. 6, row A) (14). Rhoptry proteins were also enriched after binding Plasmodium glycoproteins to the WGA-1 resin (Table 1).…”

Section: Resultsmentioning

confidence: 97%

“…Antibodies to Plasmodium proteins which are present in the ER (Pf39), food vacuole (DPAP1), and plasma membrane (MSP1-19) were obtained from MR4 (30,51). An antibody to RhopH3 was a generous gift from J. F. Dubremetz (14).…”

Section: Methodsmentioning

confidence: 99%

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Suggestive Evidence for Darwinian Selection against Asparagine-Linked Glycans of Plasmodium falciparum and Toxoplasma gondii

et al. 2010

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We are interested in asparagine-linked glycans (N-glycans) of Plasmodium falciparum and Toxoplasma gondii, because their N-glycan structures have been controversial and because we hypothesize that there might be selection against N-glycans in nucleus-encoded proteins that must pass through the endoplasmic reticulum (ER) prior to threading into the apicoplast. In support of our hypothesis, we observed the following. First, in protists with apicoplasts, there is extensive secondary loss of Alg enzymes that make lipid-linked precursors to N-glycans. Theileria makes no N-glycans, and Plasmodium makes a severely truncated N-glycan precursor composed of one or two GlcNAc residues. Second, secreted proteins of Toxoplasma, which uses its own 10-sugar precursor (Glc 3 Man 5 GlcNAc 2 ) and the host 14-sugar precursor (Glc 3 Man 9 GlcNAc 2 ) to make N-glycans, have very few sites for N glycosylation, and there is additional selection against N-glycan sites in its apicoplasttargeted proteins. Third, while the GlcNAc-binding Griffonia simplicifolia lectin II labels ER, rhoptries, and surface of plasmodia, there is no apicoplast labeling. Similarly, the antiretroviral lectin cyanovirin-N, which binds to N-glycans of Toxoplasma, labels ER and rhoptries, but there is no apicoplast labeling. We conclude that possible selection against N-glycans in protists with apicoplasts occurs by eliminating N-glycans (Theileria), reducing their length (Plasmodium), or reducing the number of N-glycan sites (Toxoplasma). In addition, occupation of N-glycan sites is markedly reduced in apicoplast proteins versus some secretory proteins in both Plasmodium and Toxoplasma.

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Section: Fig 4 Deconvolving Micrographs Of Plasmodium-infected Rbcssupporting

confidence: 70%

Section: Resultsmentioning

confidence: 97%

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Suggestive Evidence for Darwinian Selection against Asparagine-Linked Glycans of Plasmodium falciparum and Toxoplasma gondii

et al. 2010

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“…Our results suggest that RAMA-E epitopes may be important for inducing more efficient antimalarial responses which develop over a Ag44 represents the C-terminal portion of RhopH3, and a previous seroepidemiological study indicated that this region is strongly immunogenic and that ongoing P. falciparum infection results in significant increases in antibody responses to the antigen (23). Monoclonal antibodies directed against epitopes within Ag44 showed growth-inhibitory properties in in vitro assays (6,7). As in vitro RBC-binding assays indicated that Ag44 harbors an RBC-binding domain (21), there appears to be a link between protection and responses to RBC-binding domains for both RAMA and RhopH3.…”

Section: Discussionmentioning

confidence: 96%

Associations between Responses to the Rhoptry-Associated Membrane Antigen of Plasmodium falciparum and Immunity to Malaria Infection

et al. 2004

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Rhoptry proteins participate in the invasion of red blood cells by merozoites during the malaria parasite's asexual-stage cycle. Interference with the rhoptry protein function has been shown to prevent invasion, and three rhoptry proteins have been suggested as potential components of a vaccine against malaria. Rhoptryassociated membrane antigen (RAMA) is a 170-kDa protein of Plasmodium falciparum which is processed to a 60-kDa mature form in the rhoptries. p60/RAMA is discharged from rhoptries of free merozoites and binds to the red-cell membrane before being internalized to form part of the parasitophorous vacuole of the newly developing ring. We examined the range of anti-RAMA responses in individuals living in an area of endemicity for malaria and determined its association with clinical immunity. RAMA is immunogenic during infections, and at least three epitopes within RAMA are recognized by hyperimmune sera in immunoblots. Sera from individuals living in a region of Vietnam where malaria is endemic possessed strong antibody responses toward two C-terminal regions of RAMA. Cytophilic antibody isotypes (immunoglobulin G1 [IgG1] and IgG3) predominated in humoral responses to both C-terminal epitopes. Acute episodes of P. falciparum infection result in significant boosting of levels of antibody to an epitope at the extreme C terminus of RAMA that harbors the red-cell-binding domain. Immunity to P. falciparum infection was linked to elevated levels of IgG3 responses to this functional domain of RAMA, suggesting that the region may contain a protective epitope useful for inclusion in a multiepitope vaccine against malaria.Plasmodium falciparum malaria is responsible for Ͼ2 million deaths each year. With the increasing resistance of Plasmodium parasites to antimalarial drugs and of the Anopheles mosquito vector to commonly available insecticides, an effective vaccine that would protect nonimmune individuals from death would be valuable. The life cycle of malaria parasites is quite complex and provides a number of potential vaccine targets. Several proteins expressed by P. falciparum during the erythrocytic stages are being investigated as candidates for a subunit vaccine, among them rhoptry-associated proteins. The most important immune response for immunity to asexual-stage infection is believed to be humoral, although cell-mediated responses may also contribute to immunity.Rhoptries are intracellular organelles of malaria parasites involved in the invasion of red blood cells (RBCs) by Plasmodium merozoites. Although their contents are only transiently accessible to antibodies, seroepidemiological studies have demonstrated the development of antibody responses to the rhoptry proteins RhopH3, RAP1, and RAP2 following infection (8,12,20,23). In vitro growth inhibition assays have indicated that antibodies directed against the RAP1 and RAP2 proteins have inhibitory effects on P. falciparum growth in in vitro culture (6,9,14,18). Moreover, immunization of Saimiri monkeys with RAP1 protected the animals from a lethal...

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“…MAbs used in this study were produced in BALB/c mice immunized with schizonts of P. falciparum as described elsewhere. 42 The hybridomas were initially screened for reactivity with P. falciparum on air-dried parasites by indirect immunofluorescence. The F1110 and F1546 mAbs were further selected on the basis of their reactivity for Pf HRP2 using recombinant antigen.…”

Section: Methodsmentioning

confidence: 99%

Recombinant antibodies specific for thePlasmodium falciparumhistidine-rich protein 2

Ravaoarisoa

Zamanka

Fusaı̈

et al. 2010

mAbs

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Characterisation of the binding sites of monoclonal antibodies reacting with the Plasmodium falciparum rhoptry protein RhopH3

Cited by 16 publications

References 35 publications

Suggestive Evidence for Darwinian Selection against Asparagine-Linked Glycans of Plasmodium falciparum and Toxoplasma gondii

Suggestive Evidence for Darwinian Selection against Asparagine-Linked Glycans of Plasmodium falciparum and Toxoplasma gondii

Associations between Responses to the Rhoptry-Associated Membrane Antigen of Plasmodium falciparum and Immunity to Malaria Infection

Recombinant antibodies specific for thePlasmodium falciparumhistidine-rich protein 2

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