title: Antibody profiles to plasmodium merozoite surface protein-1 in Cambodian adults during an active surveillance cohort with nested treatment study.
abstract: BACKGROUND
  In addition to evidence for a protective role of antibodies to the malaria blood stage antigen merozoite surface protein 1 (MSP1), MSP1 antibodies are also considered as a marker of past malaria exposure in sero-epidemiological studies.
  
  
  METHODS
  In order to better assess the potential use of MSP1 serology in malaria chemoprophylaxis trials in endemic areas, an analysis for the prevalence of antibodies to both Plasmodium falciparum and Plasmodium vivax MSP142 in healthy Cambodian adults was conducted at two sites as part of an active, observational cohort evaluating the efficacy of dihydroartemisinin-piperaquine (DP) for uncomplicated malaria (ClinicalTrials.gov identifier NCT01280162).
  
  
  RESULTS
  Rates of baseline sero-positivity were high (59 and 73% for PfMSP142 and PvMSP142, respectively), and titers higher in those who lived in a higher transmission area, although there was little correlation in titers between the two species. Those volunteers who subsequently went on to develop malaria had higher baseline MSP142 titers than those who did not for both species. Titers to both antigens remained largely stable over the course of the 4-6 month study, except in those infected with P. falciparum who had multiple recurrences.
  
  
  CONCLUSIONS
  These findings illuminate the difficulties in using MSP142 serology as either a screening criterion and/or biomarker of exposure in chemoprophylaxis studies. Further work remains to identify useful markers of malarial infection and/or immunity.
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. michele.spring.ctr@afrims.org.
authors.forename: Michele D
authors.initials: MD
authors.lastname: Spring
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. sathitp.ca@afrims.org.
authors.forename: Sathit
authors.initials: S
authors.lastname: Pichyangkul
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. chanthapl@afrims.org.
authors.forename: Chanthap
authors.initials: C
authors.lastname: Lon
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. panitaG.fsn@afrims.org.
authors.forename: Panita
authors.initials: P
authors.lastname: Gosi
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. kosolY.fsn@afrims.org.
authors.forename: Kosol
authors.initials: K
authors.lastname: Yongvanichit
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. utaiwans.fsn@afrims.org.
authors.forename: Utaiwan
authors.initials: U
authors.lastname: Srichairatanakul
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. ampornL.fsn@afrims.org.
authors.forename: Amporn
authors.initials: A
authors.lastname: Limsalakpeth
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. chaiyapornc.ca@afrims.org.
authors.forename: Chaiyaporn
authors.initials: C
authors.lastname: Chaisatit
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. channs.ctr@afrims.org.
authors.forename: Soklyda
authors.initials: S
authors.lastname: Chann
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. sabaithipS.fsn@afrms.org.
authors.forename: Sabaithip
authors.initials: S
authors.lastname: Sriwichai
authors.affiliation: Center of Excellence for Biomedical and Public Health Informatics (BIOPHICS), Bangkok, Thailand. montidaa@biophics.org.
authors.forename: Montida
authors.initials: M
authors.lastname: Auayapon
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. suwannac2.fsn@afrims.org.
authors.forename: Suwanna
authors.initials: S
authors.lastname: Chaorattanakawee
authors.affiliation: Walter Reed Army Institute of Research, Silver Spring, MD, USA. sheetij.dutta.civ@mail.mil.
authors.forename: Sheetij
authors.initials: S
authors.lastname: Dutta
authors.affiliation: Royal Cambodian Armed Forces, Phnom Penh, Cambodia. satharathprom@yahoo.com.
authors.forename: Satharath
authors.initials: S
authors.lastname: Prom
authors.affiliation: National Center for Parasitology, Entomology and Malaria Control (CNM), Phnom Penh, Cambodia. mengchuor@gmail.com.
authors.forename: Char
authors.initials: C
authors.lastname: Meng Chour
authors.affiliation: SUNY-Upstate Medical University, Syracuse, NY, USA. douglas.walsh@va.gov.
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Walsh
authors.affiliation: Walter Reed Army Institute of Research, Silver Spring, MD, USA. evelina.angov.civ@mail.mil.
authors.forename: Evelina
authors.initials: E
authors.lastname: Angov
authors.affiliation: Armed Forces Research Institute of Medical Sciences (AFRIMS), Bangkok, Thailand. david.saunders@afrims.org.
authors.forename: David L
authors.initials: DL
authors.lastname: Saunders
mesh_terms: D000328:Adult; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000276:immunology; D037621:Artemisinins / Q000627:therapeutic use; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008288:Malaria / Q000188:drug therapy / Q000276:immunology; D016778:Malaria, Falciparum / Q000188:drug therapy / Q000276:immunology*; D008297:Male; D020066:Merozoite Surface Protein 1 / Q000276:immunology*; D010963:Plasmodium falciparum / Q000276:immunology / Q000472:pathogenicity; D010966:Plasmodium vivax / Q000276:immunology / Q000472:pathogenicity; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D037621:Artemisinins; D020066:Merozoite Surface Protein 1; C039060:artenimol