title: Memory B-cell and antibody responses induced by Plasmodium falciparum sporozoite immunization.
abstract: BACKGROUND
  Immunization of healthy volunteers during receipt of chemoprophylaxis with Plasmodium falciparum sporozoites (CPS-immunization) induces sterile protection from malaria. Antibody responses have long been known to contribute to naturally acquired immunity against malaria, but their association with sterile protection after whole sporozoite immunization is not well established. We therefore studied the induction and kinetics of malaria parasite antigen-specific antibodies and memory B-cells (MBCs) during CPS-immunization and their correlation with protection from challenge infection.
  
  
  METHODS
  We assessed humoral reactivity to 9 antigens representing different stages of the life cycle of P. falciparum by performing standardized MBC enzyme-linked immunospot and enzyme-linked immunosorbent assays on peripheral blood mononuclear cells and plasma samples from 38 Dutch volunteers enrolled in 2 randomized controlled clinical trials.
  
  
  RESULTS
  MBCs and antibodies recognizing pre-erythrocytic and cross-stage antigens were gradually acquired during CPS-immunization. The magnitude of these humoral responses did not correlate with protection but directly reflected parasite exposure in CPS-immunization and challenge.
  
  
  CONCLUSIONS
  Humoral responses to the malarial antigens circumsporozoite protein, liver-stage antigen-1, apical membrane antigen-1, and merozoite surface protein-1 do not to predict protection from challenge infection but can be used as sensitive marker of recent parasite exposure.
  
  
  BACKGROUND
  NCT01236612 and NCT01218893.
authors: Department of Medical Microbiology, Radboud university medical center, Nijmegen Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom.
authors: Wiebke
authors: W
authors: Nahrendorf
authors: Department of Medical Microbiology, Radboud university medical center, Nijmegen.
authors: Anja
authors: A
authors: Scholzen
authors: Department of Medical Microbiology, Radboud university medical center, Nijmegen.
authors: Else M
authors: EM
authors: Bijker
authors: Department of Medical Microbiology, Radboud university medical center, Nijmegen.
authors: Anne C
authors: AC
authors: Teirlinck
authors: Department of Medical Microbiology, Radboud university medical center, Nijmegen.
authors: Guido J H
authors: GJ
authors: Bastiaens
authors: Department of Infectious Diseases, Leiden University Medical Center, The Netherlands.
authors: Remko
authors: R
authors: Schats
authors: Department of Medical Microbiology, Radboud university medical center, Nijmegen.
authors: Cornelus C
authors: CC
authors: Hermsen
authors: Department of Infectious Diseases, Leiden University Medical Center, The Netherlands.
authors: Leo G
authors: LG
authors: Visser
authors: Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom.
authors: Jean
authors: J
authors: Langhorne
authors: Department of Medical Microbiology, Radboud university medical center, Nijmegen.
authors: Robert W
authors: RW
authors: Sauerwein
mesh_terms: D000328:Adult; D000913:Antibodies, Protozoan / Q000097:blood*; D001402:B-Lymphocytes / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D058501:Enzyme-Linked Immunospot Assay; D064368:Healthy Volunteers; D006801:Humans; D007114:Immunization / Q000379:methods*; D007156:Immunologic Memory; D017780:Malaria Vaccines / Q000008:administration & dosage / Q000276:immunology*; D010963:Plasmodium falciparum / Q000276:immunology*; D034101:Sporozoites / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D017780:Malaria Vaccines
keywords: Plasmodium; antibody; immunization; malaria; memory B-cell; protection; sporozoite