Strain-Transcending Inhibitory Antibodies against Homologous and Heterologous Strains of Duffy Binding Protein region II

PLoS One. 2016 May 4;11(5):e0154577. doi: 10.1371/journal.pone.0154577. eCollection 2016.

Abstract

Duffy binding protein region II (DBPII) is a promising vaccine candidate against vivax malaria. However, polymorphisms of DBPII are the major obstacle to designing a successful vaccine. Here, we examined whether anti-DBPII antibodies from individual P. vivax exposures provide strain-transcending immunity and whether their presence is associated with DBPII haplotypes found in patients with acute P. vivax. The ability of antibodies to inhibit DBL-TH-erythrocyte binding was tested by COS7 erythrocyte binding inhibition assay. Seven samples of high responders (HR) were identified from screening anti-DBPII levels. HR no.3 and HR no.6 highly inhibited all DBL-TH binding to erythrocytes, by >80%. Antibodies from these two patients' plasma had the potential to be broadly inhibitory against DBL-TH1, -TH2, -TH6, -TH7, -TH8 and -TH9 haplotypes when plasma was serially diluted from 1:500 to 1:2000. To further examine the association of DBPII haplotypes and the ability of antibodies to broadly inhibit DBL-TH variants, the individual samples underwent sequencing analysis and the inhibitory function of the anti-DBPII antibodies was tested. The patterns of DBPII polymorphisms in acute patients were classified into two groups, DBPII Sal I (55%) and DBL-TH variants (45%). Plasma from Sal I and DBPII-TH patients who had the highest inhibition against Sal I or DBL-TH4 and -TH5 was serially diluted from 1:500 to 1:2000 and their inhibitory capacity was tested against a panel of DBL-TH haplotypes. Results provided evidence of both strain-transcending inhibition as well as strain-specific inhibition by antibodies that blocked erythrocyte binding against some DBL-TH variants and against homologous alleles. This study demonstrated broad inhibition by anti-DBPII antibodies against DBL-TH haplotypes in natural P. vivax exposed individuals. The identification of conserved epitopes among DBL-TH may have implications for vaccine development of a DBPII-based vaccine against diverse P. vivax infections.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Protozoan / blood
  • Antibodies, Protozoan / immunology*
  • Antigens, Protozoan / chemistry
  • Antigens, Protozoan / genetics
  • Antigens, Protozoan / immunology*
  • Haplotypes
  • Humans
  • Malaria Vaccines / genetics
  • Malaria Vaccines / immunology
  • Malaria, Vivax / immunology
  • Malaria, Vivax / prevention & control
  • Plasmodium vivax / classification
  • Plasmodium vivax / genetics
  • Plasmodium vivax / immunology*
  • Polymorphism, Genetic
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics
  • Protozoan Proteins / immunology*
  • Receptors, Cell Surface / chemistry
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / immunology*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Species Specificity
  • Thailand

Substances

  • Antibodies, Protozoan
  • Antigens, Protozoan
  • Duffy antigen binding protein, Plasmodium
  • Malaria Vaccines
  • Protozoan Proteins
  • Receptors, Cell Surface
  • Recombinant Proteins