title: Plasmodium falciparum malaria in the Peruvian Amazon, a region of low transmission, is associated with immunologic memory.
abstract: The development of clinical immunity to Plasmodium falciparum malaria is thought to require years of parasite exposure, a delay often attributed to difficulties in developing protective antibody levels. In this study, we evaluated several P. falciparum vaccine candidate antigens, including apical membrane antigen 1 (AMA-1), circumsporozoite protein (CSP), erythrocyte binding antigen 175 (EBA-175), and the 19-kDa region of merozoite surface protein 1 (MSP1(19)). After observing a more robust antibody response to MSP1(19), we evaluated the magnitude and longevity of IgG responses specific to this antigen in Peruvian adults and children before, during, and after P. falciparum infection. In this low-transmission region, even one reported prior infection was sufficient to produce a positive anti-MSP1(19) IgG response for >5 months in the absence of reinfection. We also observed an expansion of the total plasmablast (CD19(+) CD27(+) CD38(high)) population in the majority of individuals shortly after infection and detected MSP1-specific memory B cells in a subset of individuals at various postinfection time points. This evidence supports our hypothesis that effective antimalaria humoral immunity can develop in low-transmission regions.
authors.affiliation: Department of Microbiology, The University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Eva H
authors.initials: EH
authors.lastname: Clark
authors.forename: Claudia J
authors.initials: CJ
authors.lastname: Silva
authors.forename: Greta E
authors.initials: GE
authors.lastname: Weiss
authors.forename: Shanping
authors.initials: S
authors.lastname: Li
authors.forename: Carlos
authors.initials: C
authors.lastname: Padilla
authors.forename: Peter D
authors.initials: PD
authors.lastname: Crompton
authors.forename: Jean N
authors.initials: JN
authors.lastname: Hernandez
authors.forename: OraLee H
authors.initials: OH
authors.lastname: Branch
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000096:biosynthesis; D000293:Adolescent; D000328:Adult; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology; D018941:Antigens, CD19 / Q000096:biosynthesis; D000953:Antigens, Protozoan / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007156:Immunologic Memory; D017780:Malaria Vaccines / Q000276:immunology; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000276:immunology* / Q000635:transmission; D008297:Male; D008565:Membrane Proteins / Q000276:immunology; D020066:Merozoite Surface Protein 1 / Q000276:immunology*; D010568:Peru / Q000453:epidemiology; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000096:biosynthesis; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D018941:Antigens, CD19; D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D017780:Malaria Vaccines; D008565:Membrane Proteins; D020066:Merozoite Surface Protein 1; D015800:Protozoan Proteins; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; C090077:apical membrane antigen I, Plasmodium; C041595:circumsporozoite protein, Protozoan; C065668:erythrocyte-binding antigen 175, Plasmodium; D051997:ADP-ribosyl Cyclase 1