Anthrax vaccine recipients lack antibody against the loop neutralizing determinant: A protective neutralizing epitope from Bacillus anthracis protective antigen.

Abstract

BACKGROUND:

Epitope-focused immunogens can elicit antibody against the loop neutralizing determinant (LND), a neutralizing epitope found within the 2β2-2β3 loop of protective antigen (PA), which can protect rabbits from high-dose inhalation challenge with Bacillus anthracis Ames strain. Interestingly, data suggests that this epitope is relatively immunosilent in rabbits and non-human primates immunized with full length PA.

METHODS:

To determine whether the LND is immunosilent among humans vaccinated with PA, we screened antisera from AVA- or placebo-vaccinees from a clinical trial for antibody reactive with the LND.

RESULTS:

AVA-vaccinee sera had significant PA-specific antibody compared to placebo-vaccinee sera; however, sera from the two cohorts were indistinguishable with regard to the frequency of individuals with antibody specific for the LND.

CONCLUSIONS:

AVA-vaccinees have a low frequency of antibody reactive with the LND. As with rabbits and non-human primates, the elicitation of LND-specific antibody in humans appears to require immunization with an epitope-focused vaccine.

• Authors: Jon Oscherwitz, Conrad P Quinn, Kemp B Cease
• Journal: Vaccine (Vaccine) Vol. 33 Issue 20 Pg. 2342-6 (May 11 2015) ISSN: 1873-2518 [Electronic] Netherlands
• PMID: 25820066 (Publication Type: Clinical Trial, Phase IV, Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2015 Elsevier Ltd. All rights reserved.

Chemical References

• Anthrax Vaccines
• Antibodies, Bacterial
• Antibodies, Neutralizing
• Antigens, Bacterial
• Bacterial Toxins
• Epitopes
• anthrax toxin

Topics

• Anthrax (prevention & control)
• Anthrax Vaccines (administration & dosage, immunology)
• Antibodies, Bacterial (blood)
• Antibodies, Neutralizing (blood)
• Antigens, Bacterial (immunology)
• Bacillus anthracis (immunology)
• Bacterial Toxins (immunology)
• Enzyme-Linked Immunosorbent Assay
• Epitopes (immunology)
• Humans