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

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 Leu(156) to Ser(170), Val(196) to Ile(210), and Ser(312) to Asn(326) 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 Leu(156)-Ser(170) and Val(196)-Ile(210) 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.

Medienart:

E-Artikel

Erscheinungsjahr:

2009

Erschienen:

2009

Enthalten in:

Zur Gesamtaufnahme - volume:284

Enthalten in:

The Journal of biological chemistry - 284(2009), 37 vom: 11. Sept., Seite 25077-86

Sprache:

Englisch

Beteiligte Personen:

Abboud, Nareen [VerfasserIn]
De Jesus, Magdia [VerfasserIn]
Nakouzi, Antonio [VerfasserIn]
Cordero, Radames J B [VerfasserIn]
Pujato, Mario [VerfasserIn]
Fiser, András [VerfasserIn]
Rivera, Johanna [VerfasserIn]
Casadevall, Arturo [VerfasserIn]

Links:

Volltext

Themen:

Anthrax toxin
Antibodies
Antigens, Bacterial
Bacterial Toxins
Epitopes
Journal Article
Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, Non-P.H.S.

Anmerkungen:

Date Completed 02.11.2009

Date Revised 23.02.2022

published: Print-Electronic

GENBANK: FJ784743, FJ784744, FJ784745, FJ784746, FJ784747, FJ784748, FJ784749, FJ784750

Citation Status MEDLINE

doi:

10.1074/jbc.M109.022061

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM190098287