Dataset Information

Identification of optimal epitopes for Plasmodium falciparum rapid diagnostic tests that target histidine-rich proteins 2 and 3.

ABSTRACT: Rapid diagnostic tests (RDTs) represent important tools to diagnose malaria infection. To improve understanding of the variable performance of RDTs that detect the major target in Plasmodium falciparum, namely, histidine-rich protein 2 (HRP2), and to inform the design of better tests, we undertook detailed mapping of the epitopes recognized by eight HRP-specific monoclonal antibodies (MAbs). To investigate the geographic skewing of this polymorphic protein, we analyzed the distribution of these epitopes in parasites from geographically diverse areas. To identify an ideal amino acid motif for a MAb to target in HRP2 and in the related protein HRP3, we used a purpose-designed script to perform bioinformatic analysis of 448 distinct gene sequences from pfhrp2 and from 99 sequences from the closely related gene pfhrp3. The frequency and distribution of these motifs were also compared to the MAb epitopes. Heat stability testing of MAbs immobilized on nitrocellulose membranes was also performed. Results of these experiments enabled the identification of MAbs with the most desirable characteristics for inclusion in RDTs, including copy number and coverage of target epitopes, geographic skewing, heat stability, and match with the most abundant amino acid motifs identified. This study therefore informs the selection of MAbs to include in malaria RDTs as well as in the generation of improved MAbs that should improve the performance of HRP-detecting malaria RDTs.

SUBMITTER: Lee N

PROVIDER: S-EPMC3318543 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Identification of optimal epitopes for Plasmodium falciparum rapid diagnostic tests that target histidine-rich proteins 2 and 3.

Lee Nelson N Gatton Michelle L ML Pelecanos Anita A Bubb Martin M Gonzalez Iveth I Bell David D Cheng Qin Q McCarthy James S JS

Journal of clinical microbiology 20120118 4

Rapid diagnostic tests (RDTs) represent important tools to diagnose malaria infection. To improve understanding of the variable performance of RDTs that detect the major target in Plasmodium falciparum, namely, histidine-rich protein 2 (HRP2), and to inform the design of better tests, we undertook detailed mapping of the epitopes recognized by eight HRP-specific monoclonal antibodies (MAbs). To investigate the geographic skewing of this polymorphic protein, we analyzed the distribution of these ...[more]

PMID: 22259210

Similar Datasets

Project description:BackgroundRapid diagnostic tests (RDTs) are central to fulfilling the WHO's recommendation for parasitologic confirmation of all suspected cases of malaria. RDT performance may be compromised when exposed to the high temperature conditions typical of most malaria endemic regions. However, a systematic method to monitor RDT quality and performance in endemic countries is lacking at the present time. Current methods to monitor RDT performance in the field include comparing results from RDTs to diagnoses made by light microscopy and observing health workers perform tests. These methods are not substitutes for direct quality control. In this study, the suitability of dried Plasmodium falciparum-infected blood as quality control samples for malaria RDTs was evaluated.MethodsThree cultured strains of P. falciparum at 200 and 2,000 parasites/?l were tested on 10 brands of RDT. After baseline testing to determine initial reactivity, aliquots of parasite-infected blood were air dried, stored at 35°C, room temperature (~25°C) or 4°C for one, four and 12 weeks and were then tested on the 10 RDTs after rehydration. Extended stability testing of dried blood stored at 4°C was done using P. falciparum strain 3D7 at 1,000 and 2,000 parasites/?l.ResultsAll dried blood samples at 2,000 parasites/?l retained reactivity (100% sensitivity) at all three temperatures and time points for all nine RDT brands that detect histidine-rich protein-2 (HRP2). The dried blood samples with 200 parasites/?l were detected by six of the nine HRP2-based RDTs at all storage temperatures and time points. The sensitivity for two of the three remaining HRP2-based RDTs was 100% up to four weeks of storage at all temperatures but dropped to 87.5% at week 12. Of the four RDTs that detect plasmodium lactate dehydrogenase (pLDH) in a pan-specific manner, alone or in combination with HRP2, the detection of pLDH in samples with 2,000 parasites/?L was 100% for two RDTs and 80% for the other two RDTs. The mean level for detection of pLDH at 200 parasites/?l was low (29%), with a range of 0% to100%, which was partly attributable to weak initial baseline reactivity. Reactivity of dried 3D7 at 1,000 and 2,000 parasites/?l stored at 4°C was retained at 100% for up to 52 weeks for both HRP2 and pLDH.ConclusionsIn the absence of native or recombinant positive control antigens, well-standardized P. falciparum-infected dried blood samples can be used as positive control samples for monitoring RDT performance, particularly with HRP2-detecting tests.

Dataset Information

Identification of optimal epitopes for Plasmodium falciparum rapid diagnostic tests that target histidine-rich proteins 2 and 3.

Publications

Identification of optimal epitopes for Plasmodium falciparum rapid diagnostic tests that target histidine-rich proteins 2 and 3.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure