Short-term in vitro culture of field isolates of Plasmodium vivax using umbilical cord blood

Udomsangpetch, Rachanee; Somsri, Sangdao; Panichakul, Tasanee; Chotivanich, Kesinee; Sirichaisinthop, Jeeraphat; Yang, Zhaoqing; Cui, Liwang; Sattabongkot, Jetsumon

doi:10.1016/j.parint.2006.12.005

Cited by 66 publications

(61 citation statements)

References 14 publications

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“…This may be partly explained by the limited conservation of known proteins associated with the P. falciparum trafficking machinery in other Plasmodium species (58). In addition, there has been only limited success in setting up short-term culture systems to support such basic studies of P. vivax (57,(59)(60)(61). However, it has not been shown if the transport machinery utilized by P. vivax is unique or if the reticulocyte cytoplasm influences export.…”

Section: Discussionmentioning

confidence: 99%

“…Using these antirPyExp2 antisera, the localizations of PfExp2 in mature RBCs and in reticulocytes harboring P. falciparum were compared. Human cord blood containing elevated levels of reticulocytes was used for the in vitro culture of P. falciparum FVO blood-stage parasites (56,57). With this system, a low number of newly invaded reticulocytes were detected upon staining with Giemsa (Fig.…”

Section: Pyexp2-positive Vesicles In the Cytoplasm Of P Yoelii 17x-imentioning

confidence: 99%

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Host Erythrocyte Environment Influences the Localization of Exported Protein 2, an Essential Component of the Plasmodium Translocon

et al. 2015

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Malaria parasites replicating inside red blood cells (RBCs) export a large subset of proteins into the erythrocyte cytoplasm to facilitate parasite growth and survival. PTEX, the parasite-encoded translocon, mediates protein transport across the parasitophorous vacuolar membrane (PVM) in Plasmodium falciparum-infected erythrocytes. Proteins exported into the erythrocyte cytoplasm have been localized to membranous structures, such as Maurer's clefts, small vesicles, and a tubovesicular network. Comparable studies of protein trafficking in Plasmodium vivax-infected reticulocytes are limited. With Plasmodium yoelii-infected reticulocytes, we identified exported protein 2 (Exp2) in a proteomic screen of proteins putatively transported across the PVM. Immunofluorescence studies showed that P. yoelii Exp2 (PyExp2) was primarily localized to the PVM. Unexpectedly, PyExp2 was also associated with distinct, membrane-bound vesicles in the reticulocyte cytoplasm. This is in contrast to P. falciparum in mature RBCs, where P. falciparum Exp2 (PfExp2) is exclusively localized to the PVM. Two P. yoelii-exported proteins, PY04481 (encoded by a pyst-a gene) and PY06203 (PypAg-1), partially colocalized with these PyExp2-positive vesicles. Further analysis revealed that with P. yoelii, Plasmodium berghei, and P. falciparum, cytoplasmic Exp2-positive vesicles were primarily observed in CD71؉ reticulocytes versus mature RBCs. In transgenic P. yoelii 17X parasites, the association of hemagglutinintagged PyExp2 with the PVM and cytoplasmic vesicles was retained, but the pyexp2 gene was refractory to deletion. These data suggest that the localization of Exp2 in mouse and human RBCs can be influenced by the host cell environment. Exp2 may function at multiple points in the pathway by which parasites traffic proteins into and through the reticulocyte cytoplasm.

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Section: Discussionmentioning

confidence: 99%

Section: Pyexp2-positive Vesicles In the Cytoplasm Of P Yoelii 17x-imentioning

confidence: 99%

Host Erythrocyte Environment Influences the Localization of Exported Protein 2, an Essential Component of the Plasmodium Translocon

et al. 2015

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“…Drug-resistant malaria has emerged to become a major public health problem. Research for the discovery of drugs with activity against P. vivax remains challenging due to the lack of a stable continuous in vitro culture system, and an in vivo primate model is inaccessible for general laboratories (12)(13)(14)(15).…”

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Role of Plasmodium vivax Dihydropteroate Synthase Polymorphisms in Sulfa Drug Resistance

Pornthanakasem

Riangrungroj

Chitnumsub

et al. 2016

Antimicrob Agents Chemother

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Dihydropteroate synthase (DHPS) is a known sulfa drug target in malaria treatment, existing as a bifunctional enzyme together with hydroxymethyldihydropterin pyrophosphokinase (HPPK). Polymorphisms in key residues of Plasmodium falciparum DHPS (PfDHPS) have been characterized and linked to sulfa drug resistance in malaria. Genetic sequencing of P. vivax dhps (Pvdhps) from clinical isolates has shown several polymorphisms at the positions equivalent to those in the Pfdhps genes conferring sulfa drug resistance, suggesting a mechanism for sulfa drug resistance in P. vivax similar to that seen in P. falciparum. To characterize the role of polymorphisms in the PvDHPS in sulfa drug resistance, various mutants of recombinant PvHPPK-DHPS enzymes were expressed and characterized. Moreover, due to the lack of a continuous in vitro culture system for P. vivax parasites, a surrogate P. berghei model expressing Pvhppk-dhps genes was established to demonstrate the relationship between sequence polymorphisms and sulfa drug susceptibility and to test the activities of PvDHPS inhibitors on the transgenic parasites. Both enzyme activity and transgenic parasite growth were sensitive to sulfadoxine to different degrees, depending on the number of mutations that accumulated in DHPS. K i values and 50% effective doses were higher for mutant PvDHPS enzymes than the wild-type enzymes. Altogether, the study provides the first evidence of sulfa drug resistance at the molecular level in P. vivax. Furthermore, the enzyme inhibition assay and the in vivo screening system can be useful tools for screening new compounds for their activities against PvDHPS.

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“…Unlike P. falciparum, the parasite preferentially invades young red blood cells, limiting its reproductive capacity and ability to adapt in continuous in vitro culture. 79,80 Without culture adaptation, the ex vivo assessment of drug susceptibility in P. vivax field isolates has been limited to clinical samples derived directly from the human host and subjected to short-term culture and drug exposure as exemplified by the schizont maturation test. [79][80][81][82] The inability to sustain in vitro growth restricts analysis of field isolates to a single time point making an assessment of reproducibility difficult.…”

mentioning

confidence: 99%

“…79,80 Without culture adaptation, the ex vivo assessment of drug susceptibility in P. vivax field isolates has been limited to clinical samples derived directly from the human host and subjected to short-term culture and drug exposure as exemplified by the schizont maturation test. [79][80][81][82] The inability to sustain in vitro growth restricts analysis of field isolates to a single time point making an assessment of reproducibility difficult. Despite its limitations, the current schizont maturation assay has demonstrated utility in discriminating parasite populations with different degrees of CQR, [83][84][85] characterizing drug susceptibility profiles of P. vivax to commonly used antimalarial drugs, 86,87 and screening susceptibility to novel therapeutic agents.…”

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confidence: 99%

Diagnosis and Treatment of Plasmodium vivax Malaria

Baird

Maguire

Price

2012

Advances in Parasitology

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Short-term in vitro culture of field isolates of Plasmodium vivax using umbilical cord blood

Cited by 66 publications

References 14 publications

Host Erythrocyte Environment Influences the Localization of Exported Protein 2, an Essential Component of the Plasmodium Translocon

Host Erythrocyte Environment Influences the Localization of Exported Protein 2, an Essential Component of the Plasmodium Translocon

Role of Plasmodium vivax Dihydropteroate Synthase Polymorphisms in Sulfa Drug Resistance

Diagnosis and Treatment of Plasmodium vivax Malaria

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