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Marquart L, Webb L, O'Rourke P, Gatton ML, Hsiang MS, Kalnoky M, Jang IK, Ntuku H, Mumbengegwi DR, Domingo GJ, McCarthy JS, Britton S. The in-vivo dynamics of Plasmodium falciparum HRP2: implications for the use of rapid diagnostic tests in malaria elimination. Malar J 2022; 21:233. [PMID: 35922803 PMCID: PMC9351188 DOI: 10.1186/s12936-022-04245-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 07/13/2022] [Indexed: 11/24/2022] Open
Abstract
Background Rapid diagnostic tests (RDTs) that rely on the detection of Plasmodium falciparum histidine-rich protein 2 (PfHRP2) have become key tools for diagnosing P. falciparum infection. The utility of RDTs can be limited by PfHRP2 persistence, however it can be a potential benefit in low transmission settings where detection of persistent PfHRP2 using newer ultra-sensitive PfHRP2 based RDTs can serve as a surveillance tool to identify recent exposure. Better understanding of the dynamics of PfHRP2 over the course of a malaria infection can inform optimal use of RDTs. Methods A previously published mathematical model was refined to mimic the production and decay of PfHRP2 during a malaria infection. Data from 15 individuals from volunteer infection studies were used to update the original model and estimate key model parameters. The refined model was applied to a cohort of patients from Namibia who received treatment for clinical malaria infection for whom longitudinal PfHRP2 concentrations were measured. Results The refinement of the PfHRP2 dynamic model indicated that in malaria naïve hosts, P. falciparum parasites of the 3D7 strain produce 33.6 × 10−15 g (95% CI 25.0–42.1 × 10−15 g) of PfHRP2 in vivo per parasite replication cycle, with an elimination half-life of 1.67 days (95% CI 1.11–3.40 days). The refined model included these updated parameters and incorporated individualized body fluid volume calculations, which improved predictive accuracy when compared to the original model. The performance of the model in predicting clearance of PfHRP2 post treatment in clinical samples from six adults with P. falciparum infection in Namibia improved when using a longer elimination half-life of 4.5 days, with 14% to 67% of observations for each individual within the predicted range. Conclusions The updated mathematical model can predict the growth and clearance of PfHRP2 during the production and decay of a mono-infection with P. falciparum, increasing the understanding of PfHRP2 antigen dynamics. This model can guide the optimal use of PfHRP2-based RDTs for reliable diagnosis of P. falciparum infection and re-infection in endemic settings, but also for malaria surveillance and elimination programmes in low transmission areas. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04245-z.
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Affiliation(s)
- Louise Marquart
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia. .,University of Queensland, Brisbane, QLD, Australia.
| | - Lachlan Webb
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Peter O'Rourke
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | | | - Michelle S Hsiang
- Department of Pediatrics, University of Texas, Southwestern, Dallas, TX, USA.,Malaria Elimination Initiative, Institute for Global Health Services, University of California, San Francisco, CA, USA.,Department of Pediatrics, University of California, San Francisco, CA, USA
| | | | | | - Henry Ntuku
- Malaria Elimination Initiative, Institute for Global Health Services, University of California, San Francisco, CA, USA
| | | | | | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,University of Queensland, Brisbane, QLD, Australia
| | - Sumudu Britton
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.,University of Queensland, Brisbane, QLD, Australia
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Kong A, Wilson SA, Ah Y, Nace D, Rogier E, Aidoo M. HRP2 and HRP3 cross-reactivity and implications for HRP2-based RDT use in regions with Plasmodium falciparum hrp2 gene deletions. Malar J 2021; 20:207. [PMID: 33926477 PMCID: PMC8086288 DOI: 10.1186/s12936-021-03739-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/19/2021] [Indexed: 01/29/2023] Open
Abstract
Background The Plasmodium falciparum antigen histidine rich protein 2 (HRP2) is a preferred target for malaria rapid diagnostic tests (RDTs) because of its abundant production by the parasite and thermal stability. As a result, a majority of RDTs procured globally target this antigen. However, previous reports from South America and recent reports from sub-Saharan Africa and Asia indicate that certain P. falciparum parasites have deletions of the gene coding for HRP2. The HRP2 antigen is paralogous to another P. falciparum antigen HRP3 and some antibodies to HRP2 cross-react with HRP3. Multiple parasites have been described with deletions of one or both hrp2 and hrp3 genes. It is unclear how the various combinations of hrp2 and hrp3 deletion genotypes affect clinical sensitivity of HRP2-based RDTs. Methods Cross-reactivity between HRP2 and HRP3 was tested on malaria RDTs using culture-adapted P. falciparum parasites with both hrp2 and hrp3 intact or with one or both genes deleted. Ten-fold serial dilutions of four culture-adapted P. falciparum parasites [3D7 (hrp2+/hrp3+), Dd2 (hrp2−/hrp3+), HB3 (hrp2+/hrp3−) and 3BD5 (hrp2−/hrp3−)] ranging from 100,000 to 0.01 parasites/µL were prepared. HRP2, Plasmodium lactate dehydrogenase (pLDH) and aldolase concentrations were determined for the diluted samples using a multiplex bead assay. The samples were subsequently tested on three RDT products designed to detect P. falciparum by HRP2 alone or in combination with pLDH. Results At parasite densities of approximately 1000 parasites/µL, parasites that expressed either hrp2 or hrp3 were detected by all three RDTs. Multiplex based antigen measurement using HRP2- conjugated beads demonstrated higher antigen concentration when both hrp2 and hrp3 genes were intact (3D7 parasites, 47.9 ng/ml) compared to HB3 (3.02 ng/mL) and Dd2 (0.20 ng/mL) strains that had one gene deleted. 3D7 at 10 parasites/µL (0.45 ng/mL) was reactive on all three RDT products whereas none of the other parasites were reactive at that density. Conclusions Above a certain antigen threshold, HRP3 cross-reactivity on HRP2-based RDTs is sufficient to mask the effects of deletions of hrp2 only. Studies of hrp2 deletion and its effects on HRP2-based RDTs must be studied alongside hrp3 deletions and include clinical sample reactivity on HRP2-based tests.
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Affiliation(s)
- Amy Kong
- Malaria Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Scott A Wilson
- Malaria Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.,The CDC Foundation, 600 Peachtree Street NE, Suite 1000, Atlanta, GA, 30308, USA
| | - Yong Ah
- Malaria Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.,The CDC Foundation, 600 Peachtree Street NE, Suite 1000, Atlanta, GA, 30308, USA
| | - Douglas Nace
- Malaria Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Eric Rogier
- Malaria Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Michael Aidoo
- Malaria Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.
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Culbertson EM, Khan AA, Muchenditsi A, Lutsenko S, Sullivan DJ, Petris MJ, Cormack BP, Culotta VC. Changes in mammalian copper homeostasis during microbial infection. Metallomics 2021; 12:416-426. [PMID: 31976503 DOI: 10.1039/c9mt00294d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Animals carefully control homeostasis of Cu, a metal that is both potentially toxic and an essential nutrient. During infection, various shifts in Cu homeostasis can ensue. In mice infected with Candida albicans, serum Cu progressively rises and at late stages of infection, liver Cu rises, while kidney Cu declines. The basis for these changes in Cu homeostasis was poorly understood. We report here that the progressive rise in serum Cu is attributable to liver production of the multicopper oxidase ceruloplasmin (Cp). Through studies using Cp-/- mice, we find this elevated Cp helps recover serum Fe levels at late stages of infection, consistent with a role for Cp in loading transferrin with Fe. Cp also accounts for the elevation in liver Cu seen during infection, but not for the fluctuations in kidney Cu. The Cu exporting ATPase ATP7B is one candidate for kidney Cu control, but we find no change in the pattern of kidney Cu loss during infection of Atp7b-/- mice, implying alternative mechanisms. To test whether fungal infiltration of kidney tissue was required for kidney Cu loss, we explored other paradigms of infection. Infection with the intravascular malaria parasite Plasmodium berghei caused a rise in serum Cu and decrease in kidney Cu similar to that seen with C. albicans. Thus, dynamics in kidney Cu homeostasis appear to be a common feature among vastly different infection paradigms. The implications for such Cu homeostasis control in immunity are discussed.
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Affiliation(s)
- Edward M Culbertson
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
| | - Aslam A Khan
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Abigael Muchenditsi
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Svetlana Lutsenko
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - David J Sullivan
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Michael J Petris
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Brendan P Cormack
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Valeria C Culotta
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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HRP2: Transforming Malaria Diagnosis, but with Caveats. Trends Parasitol 2020; 36:112-126. [DOI: 10.1016/j.pt.2019.12.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/29/2019] [Accepted: 12/02/2019] [Indexed: 11/23/2022]
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Plucinski MM, McElroy PD, Dimbu PR, Fortes F, Nace D, Halsey ES, Rogier E. Clearance dynamics of lactate dehydrogenase and aldolase following antimalarial treatment for Plasmodium falciparum infection. Parasit Vectors 2019; 12:293. [PMID: 31182154 PMCID: PMC6558726 DOI: 10.1186/s13071-019-3549-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 06/01/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lingering post-treatment parasite antigen in blood complicates malaria diagnosis through antigen detection. Characterization of antigen clearance dynamics is important for interpretation of positive antigen detection tests. RESULTS We used a bead-based serological assay to measure lactate dehydrogenase (LDH), aldolase (Aldo), and histidine-rich protein 2 (HRP2) levels in 196 children with Plasmodium falciparum malaria treated with effective antimalarials and followed for 28 to 42 days as part of therapeutic efficacy studies in Angola. Compared to pre-treatment levels, antigen concentrations two days after treatment declined by 99.7% for LDH, 96.3% for Aldo, and 54.6% for HRP2. After Day 2, assuming a first-order kinetics clearance model, half-lives of the antigens were 1.8 days (95% CI: 1.5-2.3) for LDH, 3.2 days (95% CI: 3.0-3.4) for Aldo, and 4.8 days (95% CI: 4.7-4.9) for HRP2. CONCLUSIONS LDH and Aldo show substantially different clearance rates than HRP2, and their presence is largely indicative of active infection.
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Affiliation(s)
- Mateusz M Plucinski
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. .,U.S. President's Malaria Initiative, CDC, Atlanta, Georgia, USA.
| | - Peter D McElroy
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.,U.S. President's Malaria Initiative, CDC, Atlanta, Georgia, USA
| | | | - Filomeno Fortes
- National Malaria Control Program, Ministry of Health, Luanda, Angola
| | - Doug Nace
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Eric S Halsey
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.,U.S. President's Malaria Initiative, CDC, Atlanta, Georgia, USA
| | - Eric Rogier
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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