title: Plasmodium falciparum: IgG subclass antibody response to merozoite surface protein-1 among Amazonian gold miners, in relation to infection status and disease expression.
abstract: The merozoite surface protein-1 (MSP-1) of Plasmodium falciparum comprises two major targets of antibody-mediated immunity: the polymorphic block 2 and the 19-kDa C-terminal domain MSP-1(19). Here, we measured antibodies to three block 2 variants and MSP-1(19) among Amazonian gold miners and examined the repertoire of block 2 variants in local parasites. Main findings were as follows: (1) Only seven different block 2 variants were found in 18 DNA sequences analyzed. (2) No major difference was observed in IgG subclass distribution of antibodies from symptomatic P. falciparum-infected patients, asymptomatic parasite carriers, and non-infected subjects. (3) Antibodies to all block 2 antigens, but not to MSP-1(19), were biased towards IgG3 across different strata of cumulative malaria exposure. (4) Similar proportions of symptomatic and asymptomatic subjects failed to recognize the block 2 variant expressed by infecting parasites. These negative results underscore the limits of conventional antibody assays to evaluate clinical immunity to malaria.
authors.affiliation: Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte (MG), Brazil.
authors.forename: Kézia K G
authors.initials: KK
authors.lastname: Scopel
authors.forename: Cor J F
authors.initials: CJ
authors.lastname: Fontes
authors.forename: Marcelo U
authors.initials: MU
authors.lastname: Ferreira
authors.forename: Erika M
authors.initials: EM
authors.lastname: Braga
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis* / Q000097:blood / Q000145:classification; D001483:Base Sequence; D001938:Brazil; D002353:Carrier State / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D016054:DNA, Protozoan / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis* / Q000097:blood / Q000145:classification; D016778:Malaria, Falciparum / Q000276:immunology*; D008297:Male; D020066:Merozoite Surface Protein 1 / Q000235:genetics / Q000276:immunology*; D008875:Middle Aged; D008906:Mining; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D016054:DNA, Protozoan; D007074:Immunoglobulin G; D020066:Merozoite Surface Protein 1; D011994:Recombinant Proteins