In vivo compartmental kinetics of Plasmodium falciparum histidine-rich protein II in the blood of humans and in BALB/c mice infected with a transgenic Plasmodium berghei parasite expressing histidine-rich protein II
Abstract Background The Plasmodium falciparum histidine-rich protein II (PfHRP2) is a common biomarker used in malaria rapid diagnostic tests (RDTs), but can persist in the blood for up to 40 days following curative treatment. The persistence of PfHRP2 presents a false positive limitation to diagnos...
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| Format: | Article |
| Language: | English |
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BMC
2019-03-01
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| Series: | Malaria Journal |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s12936-019-2712-3 |
| _version_ | 1819163790730592256 |
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| author | Kristin E. Poti Amanda E. Balaban Priya Pal Tamaki Kobayashi Daniel E. Goldberg Photini Sinnis David J. Sullivan |
| author_facet | Kristin E. Poti Amanda E. Balaban Priya Pal Tamaki Kobayashi Daniel E. Goldberg Photini Sinnis David J. Sullivan |
| author_sort | Kristin E. Poti |
| collection | DOAJ |
| description | Abstract Background The Plasmodium falciparum histidine-rich protein II (PfHRP2) is a common biomarker used in malaria rapid diagnostic tests (RDTs), but can persist in the blood for up to 40 days following curative treatment. The persistence of PfHRP2 presents a false positive limitation to diagnostic interpretation. However, the in vivo dynamics and compartmentalization underlying PfHRP2 persistence have not been fully characterized in the plasma and erythrocyte (RBC) fraction of the whole blood. Methods The kinetics and persistence of PfHRP2 in the plasma and RBC fractions of the whole blood were investigated post-treatment in human clinical samples and samples isolated from BALB/c mice infected with a novel transgenic Plasmodium berghei parasite engineered to express PfHRP2 (PbPfHRP2). Results PfHRP2 levels in human RBCs were consistently 20–40 times greater than plasma levels, even post-parasite clearance. PfHRP2 positive, DNA negative, once-infected RBCs were identified in patients that comprised 0.1–1% of total RBCs for 6 and 12 days post-treatment, even post-atovaquone–proguanil regimens. Transgenic PbPfHRP2 parasites in BALB/c mice produced and exported tgPfHRP2 to the RBC cytosol similar to P. falciparum. As in humans, tgPfHRP2 levels were found to be approximately 20-fold higher within the RBC fraction than the plasma post-treatment. RBC localized tgPfHRP2 persisted longer than tgPfHRP2 in the plasma after curative treatment. tgPfHRP2 positive, but DNA negative once-infected RBCs were also detected in mouse peripheral blood for 7–9 days after curative treatment. Conclusions The data suggest that persistence of PfHRP2 is due to slower clearance of protein from the RBC fraction of the whole blood. This appears to be a result of the presence PfHRP2 in previously infected, pitted cells, as opposed to PfHRP2 binding naïve RBCs in circulation post-treatment. The results thus confirm that the extended duration of RDT positivity after parasite clearance is likely due to pitted, once-infected RBCs that remain positive for PfHRP2. |
| first_indexed | 2024-12-22T17:49:44Z |
| format | Article |
| id | doaj.art-c454efff375c4f9cb1ffbb3ab51b40e7 |
| institution | Directory Open Access Journal |
| issn | 1475-2875 |
| language | English |
| last_indexed | 2024-12-22T17:49:44Z |
| publishDate | 2019-03-01 |
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| series | Malaria Journal |
| spelling | doaj.art-c454efff375c4f9cb1ffbb3ab51b40e72022-12-21T18:18:13ZengBMCMalaria Journal1475-28752019-03-0118111510.1186/s12936-019-2712-3In vivo compartmental kinetics of Plasmodium falciparum histidine-rich protein II in the blood of humans and in BALB/c mice infected with a transgenic Plasmodium berghei parasite expressing histidine-rich protein IIKristin E. Poti0Amanda E. Balaban1Priya Pal2Tamaki Kobayashi3Daniel E. Goldberg4Photini Sinnis5David J. Sullivan6Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthDepartment of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthDivision of Infectious Diseases, Department of Medicine, Washington University School of MedicineJohns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public HealthDivision of Infectious Diseases, Department of Medicine, Washington University School of MedicineDepartment of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthDepartment of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthAbstract Background The Plasmodium falciparum histidine-rich protein II (PfHRP2) is a common biomarker used in malaria rapid diagnostic tests (RDTs), but can persist in the blood for up to 40 days following curative treatment. The persistence of PfHRP2 presents a false positive limitation to diagnostic interpretation. However, the in vivo dynamics and compartmentalization underlying PfHRP2 persistence have not been fully characterized in the plasma and erythrocyte (RBC) fraction of the whole blood. Methods The kinetics and persistence of PfHRP2 in the plasma and RBC fractions of the whole blood were investigated post-treatment in human clinical samples and samples isolated from BALB/c mice infected with a novel transgenic Plasmodium berghei parasite engineered to express PfHRP2 (PbPfHRP2). Results PfHRP2 levels in human RBCs were consistently 20–40 times greater than plasma levels, even post-parasite clearance. PfHRP2 positive, DNA negative, once-infected RBCs were identified in patients that comprised 0.1–1% of total RBCs for 6 and 12 days post-treatment, even post-atovaquone–proguanil regimens. Transgenic PbPfHRP2 parasites in BALB/c mice produced and exported tgPfHRP2 to the RBC cytosol similar to P. falciparum. As in humans, tgPfHRP2 levels were found to be approximately 20-fold higher within the RBC fraction than the plasma post-treatment. RBC localized tgPfHRP2 persisted longer than tgPfHRP2 in the plasma after curative treatment. tgPfHRP2 positive, but DNA negative once-infected RBCs were also detected in mouse peripheral blood for 7–9 days after curative treatment. Conclusions The data suggest that persistence of PfHRP2 is due to slower clearance of protein from the RBC fraction of the whole blood. This appears to be a result of the presence PfHRP2 in previously infected, pitted cells, as opposed to PfHRP2 binding naïve RBCs in circulation post-treatment. The results thus confirm that the extended duration of RDT positivity after parasite clearance is likely due to pitted, once-infected RBCs that remain positive for PfHRP2.http://link.springer.com/article/10.1186/s12936-019-2712-3MalariaHistidine-rich protein IIHRP2PersistenceOnce-infected RBCsErythrocyte pitting |
| spellingShingle | Kristin E. Poti Amanda E. Balaban Priya Pal Tamaki Kobayashi Daniel E. Goldberg Photini Sinnis David J. Sullivan In vivo compartmental kinetics of Plasmodium falciparum histidine-rich protein II in the blood of humans and in BALB/c mice infected with a transgenic Plasmodium berghei parasite expressing histidine-rich protein II Malaria Journal Malaria Histidine-rich protein II HRP2 Persistence Once-infected RBCs Erythrocyte pitting |
| title | In vivo compartmental kinetics of Plasmodium falciparum histidine-rich protein II in the blood of humans and in BALB/c mice infected with a transgenic Plasmodium berghei parasite expressing histidine-rich protein II |
| title_full | In vivo compartmental kinetics of Plasmodium falciparum histidine-rich protein II in the blood of humans and in BALB/c mice infected with a transgenic Plasmodium berghei parasite expressing histidine-rich protein II |
| title_fullStr | In vivo compartmental kinetics of Plasmodium falciparum histidine-rich protein II in the blood of humans and in BALB/c mice infected with a transgenic Plasmodium berghei parasite expressing histidine-rich protein II |
| title_full_unstemmed | In vivo compartmental kinetics of Plasmodium falciparum histidine-rich protein II in the blood of humans and in BALB/c mice infected with a transgenic Plasmodium berghei parasite expressing histidine-rich protein II |
| title_short | In vivo compartmental kinetics of Plasmodium falciparum histidine-rich protein II in the blood of humans and in BALB/c mice infected with a transgenic Plasmodium berghei parasite expressing histidine-rich protein II |
| title_sort | in vivo compartmental kinetics of plasmodium falciparum histidine rich protein ii in the blood of humans and in balb c mice infected with a transgenic plasmodium berghei parasite expressing histidine rich protein ii |
| topic | Malaria Histidine-rich protein II HRP2 Persistence Once-infected RBCs Erythrocyte pitting |
| url | http://link.springer.com/article/10.1186/s12936-019-2712-3 |
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