title: Low prevalence of antibodies to preerythrocytic but not blood-stage Plasmodium falciparum antigens in an area of unstable malaria transmission compared to prevalence in an area of stable malaria transmission.
abstract: In areas where levels of transmission of Plasmodium falciparum are high and stable, the age-related acquisition of high-level immunoglobulin G (IgG) antibodies to preerythrocytic circumsporozoite protein (CSP) and liver-stage antigen 1 (LSA-1) has been associated with protection from clinical malaria. In contrast, age-related protection from malaria develops slowly or not at all in residents of epidemic-prone areas with unstable low levels of malaria transmission. We hypothesized that this suboptimal clinical and parasitological immunity may in part be due to reduced antibodies to CSP or LSA-1 and/or vaccine candidate blood-stage antigens. Frequencies and levels of IgG antibodies to CSP, LSA-1, thrombospondin-related adhesive protein (TRAP), apical membrane antigen 1 (AMA-1), erythrocyte binding antigen 175 (EBA-175), and merozoite surface protein 1 (MSP-1) were compared in 243 Kenyans living in a highland area of unstable transmission and 210 residents of a nearby lowland area of stable transmission. Levels of antibodies to CSP, LSA-1, TRAP, and AMA-1 in the oldest age group (>40 years) in the unstable transmission area were lower than or similar to those of children 2 to 6 years old in the stable transmission area. Only 3.3% of individuals in the unstable transmission area had high levels of IgG (>2 arbitrary units) to both CSP and LSA-1, compared to 43.3% of individuals in the stable transmission area. In contrast, antibody levels to and frequencies of MSP-1 and EBA-175 were similar in adults in areas of stable and unstable malaria transmission. Suboptimal immunity to malaria in areas of unstable malaria transmission may relate in part to infrequent high-level antibodies to preerythrocytic antigens and AMA-1.
authors.affiliation: University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Noland
authors.forename: Brett
authors.initials: B
authors.lastname: Hendel-Paterson
authors.forename: Xinan M
authors.initials: XM
authors.lastname: Min
authors.forename: Ann M
authors.initials: AM
authors.lastname: Moormann
authors.forename: John M
authors.initials: JM
authors.lastname: Vulule
authors.forename: David L
authors.initials: DL
authors.lastname: Narum
authors.forename: David E
authors.initials: DE
authors.lastname: Lanar
authors.forename: James W
authors.initials: JW
authors.lastname: Kazura
authors.forename: Chandy C
authors.initials: CC
authors.lastname: John
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood* / Q000276:immunology; D000953:Antigens, Protozoan / Q000097:blood / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007630:Kenya / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000276:immunology* / Q000635:transmission*; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum; D015995:Prevalence
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G