The Resistance Factor to<i>Plasmodium vivax</i>in Blacks

Miller, Louis H.; Mason, Steven J.; Clyde, David F.; McGinniss, Mary H.

doi:10.1056/nejm197608052950602

Cited by 1,170 publications

(813 citation statements)

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“…Moreover, mixed infections are either randomly distributed [31,32] or there might be a short age of LM-detected mixed infections [28]. Apart from differences in a wide range of ecological factors (such as climate and Anopheline vector species), these contrasting observations in P. malariae epidemiology could be linked to the virtual absence of Plasmodium vivax infections in many African populations because of the lack of the Duffy blood-group-antigen, which P. vivax requires to invade red blood cells [33]. Interestingly, Smith et al reported that in Wosera, PNG, P. vivax infections might be associated with an antagonistic effect on P. malariae infections [34].…”

Section: Variation In Parasite Prevalencementioning

confidence: 99%

“…However, the fact that P. ovale has been found to be most prevalent in areas of West Africa, where P. vivax is almost absent because of the high prevalence of the Duffy blood-group-negative phenotype [33], might also indicate a negative interaction between these two species. Because P. ovale prevalence and parasitemia are consistently low, it is often the case that there are insufficient observations to enable meaningful statistical evaluations regarding interactions between P. ovale and the other malaria parasite species that infect humans.…”

Section: Why Are P Malariae and P Ovale Infections Still Important?mentioning

confidence: 99%

See 1 more Smart Citation

Plasmodium malariae and Plasmodium ovale – the ‘bashful’ malaria parasites

Müeller

Zimmerman

Reeder

2007

Trends in Parasitology

264

245

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Although Plasmodium malariae was first described as an infectious disease of humans by Golgi in 1886 and Plasmodium ovale identified by Stevens in 1922, there are still large gaps in our knowledge of the importance of these infections as causes of malaria in different parts of the world. They have traditionally been thought of as mild illnesses that are caused by rare and, in case of P. ovale, short-lived parasites. However, recent advances in sensitive PCR diagnosis are causing a re-evaluation of this assumption. Low-level infection seems to be common across malaria-endemic areas, often as complex mixed infections. The potential interactions of P. malariae and P. ovale with Plasmodium falciparum and Plasmodium vivax might explain some basic questions of malaria epidemiology, and understanding these interactions could have an important influence on the deployment of interventions such as malaria vaccines. Geographical distributionAlthough distribution of Plasmodium malariae infection is reported as being patchy, it has been observed in all major malaria-endemic regions of the world [1]. P. malariae infections are most common in sub-Saharan Africa and the southwest Pacific, where age-specific prevalence in mass blood surveys have exceeded 15-30% [2][3][4][5][6][7][8]. By contrast, when P. malariae has been detected in malaria-endemic regions of Asia [9][10][11][12], the Middle East [13], South America [14] and Central America [15], it is observed as an infrequent infection, with blood-smear light microscopy (LM) prevalence rarely exceeding 1-2%. Much higher levels of infection were, however, found in montagnard refugees from the Cambodian-Vietnamese border [16]. In South America, P. malariae is thought to be a zoonotic infection because the genetically identical Plasmodium brasilianum infects new-world monkeys [17] and both monkeys and humans in endemic areas show high levels of seropositivity to P. malariae and P. brasilianum antigens [18].Plasmodium ovale was thought to have a much more limited distribution, with endemic transmission traditionally described as being limited to areas of tropical Africa, New Guinea, the eastern parts of Indonesia and the Philippines [19,20]. Infections with P. ovale, however, have also been reported in the Middle East [13], the Indian subcontinent [21] and different parts of Southeast Asia [11,22,23]. In West Africa (and to a lesser extent Central Africa), age specific LM prevalence of >10% have been observed [3,6] places where P. ovale is observed, it is relatively uncommon and its prevalence (as detected by LM) rarely exceeds 3-5% [22,[24][25][26].Indepth descriptions of the epidemiology of both infections based upon LM data are, thus, restricted almost exclusively to highly endemic areas in Africa and the Southwest Pacific. Detailed epidemiological studies from South America and Asia are lacking. Variation in parasite prevalenceIn West Africa, P. malariae prevalence has been reported to peak at ages similar to those of P. falciparum (i.e. in children under ten years of...

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Section: Variation In Parasite Prevalencementioning

confidence: 99%

Section: Why Are P Malariae and P Ovale Infections Still Important?mentioning

confidence: 99%

Plasmodium malariae and Plasmodium ovale – the ‘bashful’ malaria parasites

Müeller

Zimmerman

Reeder

2007

Trends in Parasitology

264

245

View full text Add to dashboard Cite

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“…Human erythrocytes lacking the Duffy antigen are not invaded by P. knowlesi merozoites, and invasion can be blocked with anti-Duffy antibodies. Humans lacking the Duffy blood group antigens are also resistant to infection by Plasmodium vivax, a human malaria, indicating that this malaria also requires the Duffy antigen as a ligand for invasion [3]. Due to this requirement, P. vivax is absent from West Africa where almost all of the population is Duffy negative.…”

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confidence: 99%

Blocking of the receptor‐mediated invasion of erythrocytes by Plasmodium knowlesi malaria with sulfated polysaccharides and glycosaminoglycans

Dalton

Hudson

Adams

et al. 1991

European Journal of Biochemistry

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Invasion of human erythrocytes by Plasmodium knowlesi requires the Duffy blood group antigen. P. knowlesi merozoites synthesize a 135-kDa polypeptide which binds to the Duffy antigen with receptor-like specificity. In this study, we show that the sulfated polysaccharide fucoidan and the glycosaminoglycan dextran sulfate inhibit the binding of the 135-kDa polypeptide to human Duffy-positive and rhesus erythrocytes while the chondroitin sulfates do not. Fucoidan and dextran sulphate also blocked the in vitro invasion of human Duffy b and rhesus erythrocytes cells by P. knowlesi merozoites. These inhibitors were more effective at blocking the binding of the 135-kDa polypeptide to human Duffy b erythrocytes than to rhesus erythrocytes, which correlated with them having a greater inhibitory effect on invasion of merozoites into human than into rhesus erythrocytes.The blocking by these sulfated sugars is not related to charge density on the polysaccharides; fucoidan with a relatively low charge density blocks binding of the 135-kDa polypeptide at 4 pg/ml, while the highly negatively charged chondroitin sulfates do not block binding even at the concentration of 1 mg/ml. Furthermore, fucoidanSepharose bound and removed the 135-kDa polypeptide from parasite culture supernatants with a selectivity equal to that of the Duffy blood group antigen. The negatively charged sulfate groups on fucoidan and dextran sulfate and the conformation in which they are held possibly mimic similarly charged groups on the Duffy antigen which bind the 135-kDa P. knowlesi polypeptide.The asexual erythrocyte cycle of malaria begins with growth and proliferation of the intraerythrocytic parasite to individual merozoites which, on rupture of the erythrocyte, invade other erythrocytes. Growth and proliferation then begins again in the newly invaded erythrocyte. Invasion of erythrocytes involves recognition of specific ligands on erythrocytes by receptors on merozoites [l]. In the case of Plasmodium knowlesi, a monkey malaria that invades human erythrocytes, at least one of these ligands is the Duffy blood group antigen [2]. Human erythrocytes lacking the Duffy antigen are not invaded by P. knowlesi merozoites, and invasion can be blocked with anti-Duffy antibodies. Humans lacking the Duffy blood group antigens are also resistant to infection by Plasmodium vivax, a human malaria, indicating that this malaria also requires the Duffy antigen as a ligand for invasion [3]. Due to this requirement, P. vivax is absent from West Africa where almost all of the population is Duffy negative.We have recently identified a 135-kDa polypeptide synthesized by P. knowlesi asexual parasites which binds to the Duffy blood group antigen with receptor-like specificity [4]. We observed, using enzyme-treated erythrocytes, that binding of the 135-kDa polypeptide correlated with the ability of merozoites to invade these cells. In the present study, we demonstrate that fucoidan, a sulfated polysaccharide, and dextran sulfate, a glycosaminoglycan, specifically block the Cor...

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“…Duffy binding protein (DBP), the first such ligand identified in micronemes of invasive malaria merozoites [2], is absolutely vital for the invasion process of Plasmodium vivax [3]. Cysteine-rich region II of the DBP comprises the prototypical Duffy binding like (DBL) ligand domain [4,5], which is also found in other erythrocyte binding proteins (EBA-175, BAEBL, JESEBL) and in cytoadherence proteins (PfEMP-1) [6].…”

Section: Plasmodium Merozoite Invasion Is a Multi-step Processmentioning

confidence: 99%

The crystal structure of P. knowlesi DBPα DBL domain and its implications for immune evasion

McHenry

Adams

2006

Trends in Biochemical Sciences

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Plasmodium vivax invasion of human erythrocytes requires that the ligand domain of the Duffybinding protein (DBP) recognize its cognate erythrocyte receptor, making DBP a potential target for therapy. The recently determined crystal structure of the orthologous DBP ligand domain of the closely related simian malaria parasite Plasmodium knowlesi provides insight into the molecular basis for receptor recognition and raises important questions about the mechanism of immune evasion employed by the malaria parasite. Plasmodium merozoite invasion is a multi-step processInvasion of erythrocytes by malaria parasites is a multi-step process involving discrete parasite ligands and host cell receptors [1]. Duffy binding protein (DBP), the first such ligand identified in micronemes of invasive malaria merozoites [2], is absolutely vital for the invasion process of Plasmodium vivax [3]. Cysteine-rich region II of the DBP comprises the prototypical Duffy binding like (DBL) ligand domain [4,5], which is also found in other erythrocyte binding proteins (EBA-175, BAEBL, JESEBL) and in cytoadherence proteins (PfEMP-1) [6]. Although the putative ligand domains of these paralogues have <30% sequence identity, these cysteine-rich regions share a core set of conserved residues (e.g., cysteines and aromatic amino acids) believed to be structurally and functionally important. DBL domains of both the human parasite P. vivax DBP and simian parasite P. knowlesi DBPα interact with the Duffy antigen receptor for chemokines (DARC) [7] on the erythrocyte surface, leading to formation of a tight junction necessary for invasion. The crystal structure of the P. knowlesi DBPα DBL domain recently reported by Singh et al provides exciting insights into the functional character of the P. vivax DBP [8]. Plasmodium knowlesi α DBL structureThe overall structure of the P. knowlesi DBPα DBL is similar to that of the F1 and F2 DBL domains of EBA-175 [9]. All twelve conserved cysteines of the P. knowlesi DBPα DBL domain are involved in intradomain disulfide bridges that delimit three DBL subdomains in the backbone, which forms a 'boomerang-shaped unit'. The pattern of disulfide bonding is identical between the P. knowlesi DBPα DBL and the F1 and F2 DBLs of P. falciparum EBA-175, although the F2 has an additional disulfide bridge. Subdomains 1, 2, and 3 have two, one and three disulfide bonds, respectively, and are comprised of twelve alpha helices (Fig. 1). Residues 15-52 form a random-coil stretch that makes up subdomain 1. The region between subdomains 1 and 2 (residues 53-63) is disordered and missing from the crystal structure, but is predicted to form a flexible linker. The 'β finger' motifs that facilitate Subdomain 2 (residues 64-180) and subdomain 3 (residues 186-307) each contain six alpha helices and are attached by a short linker segment. Subdomain 3 forms a large loop stabilized by three disulfide bridges with alpha helix 8 atop alpha helices 7 and 9; however, the functional role of the subdomain 3 structure is unclear. Proposed DARC Re...

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The Resistance Factor toPlasmodium vivaxin Blacks

Cited by 1,170 publications

References 10 publications

Plasmodium malariae and Plasmodium ovale – the ‘bashful’ malaria parasites

Plasmodium malariae and Plasmodium ovale – the ‘bashful’ malaria parasites

Blocking of the receptor‐mediated invasion of erythrocytes by Plasmodium knowlesi malaria with sulfated polysaccharides and glycosaminoglycans

The crystal structure of P. knowlesi DBPα DBL domain and its implications for immune evasion

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