MilliporeSigma
  • Home
  • Search Results
  • Immunogenicity of the Plasmodium falciparum PfEMP1-VarO Adhesin: Induction of Surface-Reactive and Rosette-Disrupting Antibodies to VarO Infected Erythrocytes.

Immunogenicity of the Plasmodium falciparum PfEMP1-VarO Adhesin: Induction of Surface-Reactive and Rosette-Disrupting Antibodies to VarO Infected Erythrocytes.

PloS one (2015-07-30)
Micheline Guillotte, Alexandre Juillerat, Sébastien Igonet, Audrey Hessel, Stéphane Petres, Elodie Crublet, Cécile Le Scanf, Anita Lewit-Bentley, Graham A Bentley, Inès Vigan-Womas, Odile Mercereau-Puijalon
ABSTRACT

Adhesion of Plasmodium falciparum-infected red blood cells (iRBC) to human erythrocytes (i.e. rosetting) is associated with severe malaria. Rosetting results from interactions between a subset of variant PfEMP1 (Plasmodium falciparum erythrocyte membrane protein 1) adhesins and specific erythrocyte receptors. Interfering with such interactions is considered a promising intervention against severe malaria. To evaluate the feasibility of a vaccine strategy targetting rosetting, we have used here the Palo Alto 89F5 VarO rosetting model. PfEMP1-VarO consists of five Duffy-Binding Like domains (DBL1-5) and one Cysteine-rich Interdomain Region (CIDR1). The binding domain has been mapped to DBL1 and the ABO blood group was identified as the erythrocyte receptor. Here, we study the immunogenicity of all six recombinant PfEMP1-VarO domains and the DBL1- CIDR1 Head domain in BALB/c and outbred OF1 mice. Five readouts of antibody responses are explored: ELISA titres on the recombinant antigen, VarO-iRBC immunoblot reactivity, VarO-iRBC surface-reactivity, capacity to disrupt VarO rosettes and the capacity to prevent VarO rosette formation. For three domains, we explore influence of the expression system on antigenicity and immunogenicity. We show that correctly folded PfEMP1 domains elicit high antibody titres and induce a homogeneous response in outbred and BALB/c mice after three injections. High levels of rosette-disrupting and rosette-preventing antibodies are induced by DBL1 and the Head domain. Reduced-alkylated or denatured proteins fail to induce surface-reacting and rosette-disrupting antibodies, indicating that surface epitopes are conformational. We also report limited cross-reactivity between some PfEMP1 VarO domains. These results highlight the high immunogenicity of the individual domains in outbred animals and provide a strong basis for a rational vaccination strategy targeting rosetting.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Formaldehyde-12C solution, 20% in H2O, 99.9 atom % 12C
Sigma-Aldrich
DL-Dithiothreitol, for molecular biology, ≥98% (HPLC), ≥99% (titration)
Sigma-Aldrich
DL-Dithiothreitol, suitable for electrophoresis, ≥99%
Sigma-Aldrich
DL-Dithiothreitol, BioXtra, ≥99.0% (titration)
Sigma-Aldrich
DL-Dithiothreitol, ≥98% (HPLC), ≥99.0% (titration)
Sigma-Aldrich
Formaldehyde solution, for molecular biology, 36.5-38% in H2O
Sigma-Aldrich
DL-Dithiothreitol, BioUltra, for molecular biology, ≥99.5% (RT)
Sigma-Aldrich
Formaldehyde solution, meets analytical specification of USP, ≥34.5 wt. %
Sigma-Aldrich
Formaldehyde solution, ACS reagent, 37 wt. % in H2O, contains 10-15% Methanol as stabilizer (to prevent polymerization)
Sigma-Aldrich
DL-Dithiothreitol, ≥99.0% (RT)
Sigma-Aldrich
DL-Dithiothreitol solution, BioUltra, for molecular biology, ~1 M in H2O
Sigma-Aldrich
DL-Dithiothreitol, BioUltra, ≥99.0% (RT)
Sigma-Aldrich
Formaldehyde solution, for molecular biology, BioReagent, ≥36.0% in H2O (T)
Supelco
DL-Dithiothreitol solution, 1 M in H2O