{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T16:34:10Z","timestamp":1787070850753,"version":"build-2736575974"},"reference-count":33,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"2","content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2024,4]]},"abstract":"\n Background & objectives:<\/jats:title>\n \n Plasmodium knowlesi<\/jats:italic>\n , a simian malaria species, is now known to infect humans. Due to disadvantages in the current diagnosis methods, many efforts have been placed into developing new methods to diagnose the disease. This study assessed the ability of the PkRAP-1 sandwich enzyme-linked immunosorbent (ELISA) to detect P\n knowlesi<\/jats:italic>\n antigens in whole blood specimens.\n <\/jats:p>\n <\/jats:sec>\n \n Methods:<\/jats:title>\n \n Western blot assay was conducted to evaluate the ability of raised mouse and rabbit anti-PkRAP-1 polyclonal antibodies to bind to the native proteins in\n P. knowlesi<\/jats:italic>\n lysate. The polyclonal antibodies were then used in sandwich ELISA to detect\n P. knowlesi<\/jats:italic>\n . In the sandwich ELISA, mouse and rabbit polyclonal antibodies were used as the capture and detection antibodies, respectively. The limit of detection (LOD) of the assay was determined using\n P. knowlesi<\/jats:italic>\n A1H1 culture and purified recombinant PkRAP-1.\n <\/jats:p>\n <\/jats:sec>\n \n Results:<\/jats:title>\n \n Western blot results showed positive reactions towards the proteins in\n P. knowlesi<\/jats:italic>\n lysate. The LOD of the assay from three technical replicates was 0.068% parasitaemia. The assay performance in detecting\n P. knowlesi<\/jats:italic>\n was 83% sensitivity and 70% specificity with positive and negative predictive values of 74% and 80%, respectively. The anti-PkRAP-1 polyclonal antibodies did not cross-react with\n P. falciparum<\/jats:italic>\n and healthy samples, but\n P. vivax<\/jats:italic>\n by detecting all 12 samples.\n <\/jats:p>\n <\/jats:sec>\n \n Interpretation & conclusion:<\/jats:title>\n \n PkRAP-1 has the potential as a biomarker for the development of a new diagnostic tool for\n P. knowlesi<\/jats:italic>\n detection. Further studies need to be conducted to establish the full potential of the usage of anti-PkRAP-1 antibodies for\n P. knowlesi<\/jats:italic>\n detection.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.4103\/jvbd.jvbd_55_23","type":"journal-article","created":{"date-parts":[[2024,6,21]],"date-time":"2024-06-21T00:03:30Z","timestamp":1718928210000},"page":"203-210","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["Detection of Plasmodium knowlesi in whole blood samples with sandwich enzyme-linked immunosorbent assay (ELISA) using rhoptry-associated protein 1 specific polyclonal antibodies"],"prefix":"10.4103","volume":"61","author":[{"given":"Wan Siti Maryam","family":"Wan Nazri","sequence":"first","affiliation":[{"name":"Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lau Yee","family":"Ling","sequence":"additional","affiliation":[{"name":"Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cheong Fei","family":"Wen","sequence":"additional","affiliation":[{"name":"Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2024,6,6]]},"reference":[{"issue":"1","key":"R1-20240830","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1186\/s40249-020-00727-x","article-title":"Prevalence of severe Plasmodium knowlesi infection and risk factors related to severe complications compared with non-severe P. knowlesi and severe P. falciparum malaria: A systematic review and meta-analysis","volume":"9","author":"Kotepui","year":"2020","journal-title":"Infect Dis Poverty"},{"issue":"7","key":"R2-20240830","doi-asserted-by":"crossref","first-page":"1248","DOI":"10.3201\/eid.1707.101017","article-title":"Severe Plasmodium knowlesi malaria in a tertiary care hospital, Sabah, Malaysia","volume":"17","author":"William","year":"2011","journal-title":"Emerg Infect Dis"},{"issue":"4","key":"R3-20240830","doi-asserted-by":"crossref","first-page":"1118","DOI":"10.1128\/JCM.03285-12","article-title":"Evaluation of the sensitivity of a pLDH-based and an aldolasebased rapid diagnostic test for diagnosis of uncomplicated and severe malaria caused by PCR-confirmed Plasmodium knowlesi, Plasmodium falciparum, and Plasmodium vivax","volume":"51","author":"Barber","year":"2013","journal-title":"J Clin Microbiol"},{"key":"R4-20240830","doi-asserted-by":"crossref","first-page":"1196","DOI":"10.1016\/j.micinf.2005.04.004","article-title":"Cerebral malaria is frequently associated with latent parasitaemia among the semi-immune population of eastern Sudan","volume":"7","author":"Hayder","year":"2005","journal-title":"Microbes Infect"},{"issue":"8","key":"R5-20240830","article-title":"Limitations of microscopy to differentiate Plasmodium species in a region co-endemic for Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi","volume":"12","author":"Barber","year":"2013","journal-title":"Malar J"},{"issue":"6","key":"R6-20240830","doi-asserted-by":"crossref","first-page":"805","DOI":"10.5858\/arpa.2011-0602-RA","article-title":"Laboratory Diagnosis of Malaria: Conventional and Rapid Diagnostic Methods","volume":"137","author":"Wilson","year":"2013","journal-title":"Arch Pathol Lab Med"},{"key":"R7-20240830","first-page":"189","article-title":"Nested PCR analysis of Plasmodium parasites","volume":"72","author":"Snounou","year":"2002","journal-title":"Methods Mol Med"},{"issue":"12","key":"R8-20240830","doi-asserted-by":"crossref","first-page":"4173","DOI":"10.1128\/JCM.00811-09","article-title":"Spurious amplification of a Plasmodium vivax small-subunit RNA gene by use of primers currently used to detect P. knowlesi","volume":"47","author":"Imwong","year":"2009","journal-title":"J Clin Microbiol"},{"key":"R9-20240830","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1186\/1475-2875-13-60","article-title":"Evaluation of three rapid diagnostic tests for the detection of human infections with Plasmodium knowlesi","volume":"13","author":"Foster","year":"2014","journal-title":"Malar J"},{"issue":"9","key":"R10-20240830","doi-asserted-by":"crossref","first-page":"1478","DOI":"10.3201\/eid1509.090358","article-title":"Human Plasmodium knowlesi infection detected by rapid diagnostic tests for malaria","volume":"15","author":"van Hellemond","year":"2009","journal-title":"Emerg Infect Dis"},{"issue":"1","key":"R11-20240830","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1016\/S0166-6851(97)00238-7","article-title":"Analysis of the processing of Plasmodium falciparum rhoptry-associated protein 1 and localization of Pr86 to schizont rhoptries and p67 to free merozoites","volume":"92","author":"Howard","year":"1998","journal-title":"Mol Biochem Parasitol"},{"issue":"8","key":"R12-20240830","doi-asserted-by":"crossref","DOI":"10.1111\/cmi.12733","article-title":"The Plasmodium rhoptry associated protein complex is important for parasitophorous vacuole membrane structure and intraerythrocytic parasite growth","volume":"19","author":"Ghosh","year":"2017","journal-title":"Cell Microbiol"},{"issue":"11","key":"R13-20240830","doi-asserted-by":"crossref","first-page":"2435","DOI":"10.1093\/emboj\/19.11.2435","article-title":"RAP1 controls rhoptry targeting of RAP2 in the malaria parasite Plasmodium falciparum","volume":"19","author":"Baldi","year":"2000","journal-title":"EMBO J"},{"issue":"1-2","key":"R14-20240830","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/0166-6851(92)90138-A","article-title":"Inhibitory monoclonal antibodies recognise epitopes adjacent to a proteolytic cleavage site on the RAP-1 protein of Plasmodium falciparum","volume":"55","author":"Harnyuttanakorn","year":"1992","journal-title":"Mol Biochem Parasitol"},{"issue":"1","key":"R15-20240830","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1128\/IAI.66.1.380-386.1998","article-title":"Analysis of inhibitory epitopes in the Plasmodium falciparum rhoptry protein RAP-1 including identification of a second inhibitory epitope","volume":"66","author":"Howard","year":"1998","journal-title":"Infect Immun"},{"issue":"4","key":"R16-20240830","doi-asserted-by":"crossref","first-page":"1053","DOI":"10.1016\/j.bbrc.2006.01.061","article-title":"The Plasmodium vivax rhoptry-associated protein 1","volume":"341","author":"Perez-Leal","year":"2006","journal-title":"Biochem Biophys Res Commun"},{"key":"R17-20240830","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/j.jbi.2014.02.013","article-title":"Sample size estimation in diagnostic test studies of biomedical informatics","volume":"48","author":"Hajian-Tilaki","year":"2014","journal-title":"J Biomed Inform"},{"issue":"4","key":"R18-20240830","doi-asserted-by":"crossref","first-page":"439","DOI":"10.1038\/nprot.2011.304","article-title":"Multisubstrate-compatible ELISA procedures for rapid and high-sensitivity immunoassays","volume":"6","author":"Dixit","year":"2011","journal-title":"Nat Protoc"},{"issue":"3","key":"R19-20240830","doi-asserted-by":"crossref","first-page":"276","DOI":"10.11613\/BM.2012.031","article-title":"Interrater reliability: the kappa statistic","volume":"22","author":"McHugh","year":"2012","journal-title":"Biochem Med (Zagreb)"},{"key":"R20-20240830","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1186\/s12936-016-1127-7","article-title":"Genetic diversity and natural selection in the rhoptry-associated protein 1 (RAP-1) of recent Plasmodium knowlesi clinical isolates from Malaysia","volume":"15","author":"Rawa","year":"2016","journal-title":"Malar J"},{"issue":"2","key":"R21-20240830","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/0166-6851(91)90184-8","article-title":"Genetic and structural relationships between components of a protective rhoptry antigen complex from Plasmodium falciparum","volume":"47","author":"Ridley","year":"1991","journal-title":"Mol Biochem Parasitol"},{"issue":"5","key":"R22-20240830","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1007\/BF00538200","article-title":"Identification and characterisation of proteins associated with the rhoptry organelles of Plasmodium falciparum merozoites","volume":"73","author":"Clark","year":"1987","journal-title":"Parasitol Res"},{"issue":"2","key":"R23-20240830","doi-asserted-by":"crossref","first-page":"93","DOI":"10.3347\/kjp.2009.47.2.93","article-title":"Malaria diagnosis: a brief review","volume":"47","author":"Tangpukdee","year":"2009","journal-title":"Korean J Parasitol"},{"key":"R24-20240830","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1186\/s12936-016-1158-0","article-title":"Novel molecular diagnostic tools for malaria elimination: a review of options from the point of view of high-throughput and applicability in resource limited settings","volume":"15","author":"Britton","year":"2016","journal-title":"Malar J"},{"issue":"4","key":"R25-20240830","first-page":"745","article-title":"Two-site sandwich ELISA for detection of Plasmodium vivax blood stage antigens using monoclonal and polyclonal antibodies","volume":"23","author":"Khusmith","year":"1992","journal-title":"Southeast Asian J Trop Med Public Health"},{"issue":"1","key":"R26-20240830","doi-asserted-by":"crossref","first-page":"12","DOI":"10.4103\/0250-474X.62229","article-title":"Monoclonal antibodies as diagnostics; an appraisal","volume":"72","author":"Siddiqui","year":"2010","journal-title":"Indian J Pharm Sci"},{"key":"R27-20240830","doi-asserted-by":"crossref","first-page":"20147","DOI":"10.1074\/jbc.M401114200","article-title":"A common cross-species function for the double epidermal growth factor-like modules of the highly divergent Plasmodium surface proteins MSP-1 and MSP-8","volume":"279","author":"Drew","year":"2004","journal-title":"J Biol Chem"},{"issue":"1","key":"R28-20240830","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1186\/s12936-018-2420-4","article-title":"In vitro invasion inhibition assay using antibodies against Plasmodium knowlesi Duffy binding protein alpha and apical membrane antigen protein 1 in human erythrocyte-adapted P. knowlesi A1-H.1 strain","volume":"17","author":"Muh","year":"2018","journal-title":"Malar J"},{"issue":"6","key":"R29-20240830","doi-asserted-by":"crossref","first-page":"e0008323","DOI":"10.1371\/journal.pntd.0008323","article-title":"Cross-species reactivity of antibodies against Plasmodium vivax blood-stage antigens to Plasmodium knowlesi","volume":"14","author":"Muh","year":"2020","journal-title":"PLoS Negl Trop Dis"},{"key":"R30-20240830","first-page":"4","article-title":"Long-term storage of proteins","author":"Carpenter","year":"2002","journal-title":"Curr Protoc Protein Sci"},{"issue":"5","key":"R31-20240830","doi-asserted-by":"crossref","DOI":"10.1101\/pdb.top79","article-title":"Stabilization of proteins for storage","volume":"2010","author":"Simpson","year":"2010","journal-title":"Cold Spring Harb Protoc"},{"issue":"6","key":"R32-20240830","doi-asserted-by":"crossref","first-page":"1012","DOI":"10.1128\/CVI.00385-07","article-title":"Enzyme-linked immunosorbent assay for detection of Plasmodium falciparum histidine-rich protein 2 in blood, plasma, and serum","volume":"15","author":"Kifude","year":"2008","journal-title":"Clin Vaccine Immunol"},{"issue":"6","key":"R33-20240830","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1093\/bjaceaccp\/mkn041","article-title":"Clinical tests: sensitivity and specificity","volume":"8","author":"Lalkhen","year":"2008","journal-title":"Continuing Education in Anaesthesia Critical Care & Pain"}],"container-title":["Journal of Vector Borne Diseases"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ovid.com\/10.4103\/jvbd.jvbd_55_23","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T15:37:39Z","timestamp":1787067459000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ovid.com\/10.4103\/jvbd.jvbd_55_23"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,4]]},"references-count":33,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2024]]}},"URL":"https:\/\/doi.org\/10.4103\/jvbd.jvbd_55_23","relation":{},"ISSN":["0972-9062"],"issn-type":[{"value":"0972-9062","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,4]]},"assertion":[{"value":"2023-03-27","name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2023-11-06","name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}}]}}