title: Acquisition and Longevity of Antibodies to Plasmodium vivax Preerythrocytic Antigens in Western Thailand.
abstract: Plasmodium vivax is now the dominant Plasmodium species causing malaria in Thailand, yet little is known about naturally acquired immune responses to this parasite in this low-transmission region. The preerythrocytic stage of the P. vivax life cycle is considered an excellent target for a malaria vaccine, and in this study, we assessed the stability of the seropositivity and the magnitude of IgG responses to three different preerythrocytic P. vivax proteins in two groups of adults from a region of western Thailand where malaria is endemic. These individuals were enrolled in a yearlong cohort study, which comprised one group that remained P. vivax free (by quantitative PCR [qPCR] detection, n = 31) and another that experienced two or more blood-stage P. vivax infections during the year of follow up (n = 31). Despite overall low levels of seropositivity, IgG positivity and magnitude were long-lived over the 1-year period in the absence of qPCR-detectable blood-stage P. vivax infections. In contrast, in the adults with two or more P. vivax infections during the year, IgG positivity was maintained, but the magnitude of the response to P. vivax circumsporozoite protein 210 (CSP210) decreased over time. These findings demonstrate that long-term humoral immunity can develop in low-transmission regions.
authors.affiliation: Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia Department of Medical Biology, University of Melbourne, Melbourne, Australia.
authors.forename: Rhea J
authors.initials: RJ
authors.lastname: Longley
authors.affiliation: The Jenner Institute, Nuffield Department of Medicine, The Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, United Kingdom.
authors.forename: Arturo
authors.initials: A
authors.lastname: Reyes-Sandoval
authors.affiliation: The Jenner Institute, Nuffield Department of Medicine, The Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, United Kingdom.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Montoya-Díaz
authors.affiliation: Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand Centre for Tropical Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Susanna
authors.initials: S
authors.lastname: Dunachie
authors.affiliation: Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: Chalermpon
authors.initials: C
authors.lastname: Kumpitak
authors.affiliation: Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: Wang
authors.initials: W
authors.lastname: Nguitragool
authors.affiliation: Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia Department of Medical Biology, University of Melbourne, Melbourne, Australia ISGlobal, Barcelona Institute for Global Health, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Ivo
authors.initials: I
authors.lastname: Mueller
authors.affiliation: Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand jetsumon.pra@mahidol.ac.th.
authors.forename: Jetsumon
authors.initials: J
authors.lastname: Sattabongkot
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000913:Antibodies, Protozoan / Q000097:blood* / Q000276:immunology; D000953:Antigens, Protozoan / Q000097:blood / Q000235:genetics / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology* / Q000502:physiology; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D007223:Infant; D008018:Life Cycle Stages; D016780:Malaria, Vivax / Q000453:epidemiology / Q000276:immunology* / Q000469:parasitology / Q000635:transmission; D008875:Middle Aged; D010966:Plasmodium vivax / Q000254:growth & development / Q000276:immunology*; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G