title: Longevity of Genotype-Specific Immune Responses to Plasmodium falciparum Merozoite Surface Protein 1 in Kenyan Children from Regions of Different Malaria Transmission Intensity.
abstract: Naturally acquired immunity to Plasmodium falciparum presents a changing landscape as malaria control programs and vaccine initiatives are implemented. Determining which immunologic indicators remain surrogates of past infection, as opposed to mediators of protection, led us to compare stability of immune responses across regions with divergent malaria transmission intensities. A repeat cross-sectional study of Kenyan children from a malaria-holoendemic area and an epidemic-prone area was used to examine longitudinal antibody and interferon-gamma (IFN-γ) responses to the 3D7 and FVO variants of merozoite surface protein 1 (MSP1). Antibodies to MSP1 were common in both study populations and did not significantly wane over a 21-month time period. IFN-γ responses were less frequent and rapidly disappeared in children after a prolonged period of no malaria transmission. Antibody and IFN-γ responses rarely correlated with each other; however, MSP1-specific IFN-γ response correlated with lack of concurrent P. falciparum parasitemia of the same genotype, though only statistically significantly in the malaria-holoendemic region (odds ratio = 0.31, 95% confidence interval = 0.12-0.84). This study affirms that antimalarial antibodies are informative for evaluation of history of malaria exposure within individuals, whereas cell-mediated immunity, though short lived under natural exposure conditions, might provide an assessment of recent infection and protection from parasitemia.
authors.affiliation: Division of Infectious Diseases, University of North Carolina, School of Medicine, Chapel Hill, North Carolina.
authors.forename: Natalie M
authors.initials: NM
authors.lastname: Bowman
authors.affiliation: Division of Infectious Diseases, University of North Carolina, School of Medicine, Chapel Hill, North Carolina. Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina. jjuliano@med.unc.edu.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Juliano
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Snider
authors.affiliation: Division of Infectious Diseases, University of North Carolina, School of Medicine, Chapel Hill, North Carolina.
authors.forename: Oksana
authors.initials: O
authors.lastname: Kharabora
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Meshnick
authors.affiliation: Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
authors.forename: John
authors.initials: J
authors.lastname: Vulule
authors.affiliation: Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University, Indianapolis, Indiana.
authors.forename: Chandy C
authors.initials: CC
authors.lastname: John
authors.affiliation: Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Moormann
mesh_terms: D002648:Child; D005260:Female; D005838:Genotype; D006801:Humans; D056724:Immunity, Humoral / Q000276:immunology*; D007630:Kenya; D016778:Malaria, Falciparum / Q000276:immunology* / Q000635:transmission; D008297:Male; D020066:Merozoite Surface Protein 1 / Q000235:genetics / Q000276:immunology*; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D013997:Time Factors
chemical_list: D020066:Merozoite Surface Protein 1