title: The breadth, but not the magnitude, of circulating memory B cell responses to P. falciparum increases with age/exposure in an area of low transmission.
abstract: BACKGROUND
  Malaria caused by Plasmodium falciparum remains a major cause of death in sub-Saharan Africa. Immunity against symptoms of malaria requires repeated exposure, suggesting either that the parasite is poorly immunogenic or that the development of effective immune responses to malaria may be impaired.
  
  
  METHODS
  We carried out two age-stratified cross-sectional surveys of anti-malarial humoral immune responses in a Gambian village where P. falciparum malaria transmission is low and sporadic. Circulating antibodies and memory B cells (MBC) to four malarial antigens were measured using ELISA and cultured B cell ELISpot.
  
  
  CONCLUSIONS
  The proportion of individuals with malaria-specific MBC and antibodies, and the average number of antigens recognised by each individual, increased with age but the magnitude of these responses did not. Malaria-specific antibody levels did not correlate with either the prevalence or median number of MBC, indicating that these two assays are measuring different aspects of the humoral immune response. Among those with immunological evidence of malaria exposure (defined as a positive response to at least one malarial antigen either by ELISA or ELISPOT), the median number of malaria-specific MBC was similar to median numbers of diphtheria-specific MBC, suggesting that the circulating memory cell pool for malaria antigens is of similar size to that for other antigens.
authors: Medical Research Council Laboratories, Fajara, Banjul, The Gambia.
authors: Sarah I
authors: SI
authors: Nogaro
authors: Julius C
authors: JC
authors: Hafalla
authors: Brigitte
authors: B
authors: Walther
authors: Edmond J
authors: EJ
authors: Remarque
authors: Kevin K A
authors: KK
authors: Tetteh
authors: David J
authors: DJ
authors: Conway
authors: Eleanor M
authors: EM
authors: Riley
authors: Michael
authors: M
authors: Walther
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000276:immunology*; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002452:Cell Count; D002465:Cell Movement / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004165:Diphtheria / Q000276:immunology; D004781:Environmental Exposure; D058501:Enzyme-Linked Immunospot Assay; D005714:Gambia / Q000453:epidemiology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory / Q000276:immunology*; D007223:Infant; D018655:Lymphocyte Count; D016778:Malaria, Falciparum / Q000097:blood / Q000453:epidemiology / Q000276:immunology* / Q000635:transmission*; D010963:Plasmodium falciparum / Q000276:immunology*; D015995:Prevalence; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G