Identification of linear epitopes in bacillus anthracis protective antigen bound by neutralizing antibodies

Nareen Abboud, Magdia De Jesus, Antonio Nakouzi, Radames J B Cordero, Mario Pujato, Andras Fiser, Johanna Rivera, Arturo Casadevall

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Protective antigen (PA), the binding subunit of anthrax toxin, is the major component in the current anthrax vaccine, but the fine antigenic structure of PA is not well defined. To identify linear neutralizing epitopes of PA, 145 overlapping peptides covering the entire sequence of the protein were synthesized. Six monoclonal antibodies (mAbs) and antisera from mice specific for PA were tested for their reactivity to the peptides by enzyme-linked immunosorbent assays. Three major linear immunodominant B-cell epitopes were mapped to residues Leu156 to Ser170, Val196 to Ile210, and Ser312 to Asn326 of the PA protein. Two mAbs with toxin-neutralizing activity recognized two different epitopes in close proximity to the furin cleavage site in domain 1. The three-dimensional complex structure of PA and its neutralizing mAbs 7.5G and 19D9 were modeled using the molecular docking method providing models for the interacting epitope and paratope residues. For both mAbs, LeTx neutralization was associated with interference with furin cleavage, but they differed in effectiveness depending on whether they bound on the N- or C-terminal aspect of the cleaved products. The two peptides containing these epitopes that include amino acids Leu156-Ser170 and Val196-Ile210 were immunogenic and elicited neutralizing antibody responses to PA. These results identify the first linear neutralizing epitopes of PA and show that peptides containing epitope sequences can elicit neutralizing antibody responses, a finding that could be exploited for vaccine design.

Original languageEnglish (US)
Pages (from-to)25077-25086
Number of pages10
JournalJournal of Biological Chemistry
Volume284
Issue number37
DOIs
StatePublished - Sep 11 2009

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Neutralizing Antibodies
Epitopes
Antigens
Monoclonal Antibodies
Furin
Peptides
Antibody Formation
Anthrax Vaccines
Antibody Binding Sites
B-Lymphocyte Epitopes
Immunodominant Epitopes
Immunosorbents
anthrax toxin
Immune Sera
Assays
Proteins
Vaccines
Enzyme-Linked Immunosorbent Assay
Amino Acids
Enzymes

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

Identification of linear epitopes in bacillus anthracis protective antigen bound by neutralizing antibodies. / Abboud, Nareen; De Jesus, Magdia; Nakouzi, Antonio; Cordero, Radames J B; Pujato, Mario; Fiser, Andras; Rivera, Johanna; Casadevall, Arturo.

In: Journal of Biological Chemistry, Vol. 284, No. 37, 11.09.2009, p. 25077-25086.

Research output: Contribution to journalArticle

Abboud, Nareen ; De Jesus, Magdia ; Nakouzi, Antonio ; Cordero, Radames J B ; Pujato, Mario ; Fiser, Andras ; Rivera, Johanna ; Casadevall, Arturo. / Identification of linear epitopes in bacillus anthracis protective antigen bound by neutralizing antibodies. In: Journal of Biological Chemistry. 2009 ; Vol. 284, No. 37. pp. 25077-25086.
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