title: Epitope-focused peptide immunogens in human use adjuvants protect rabbits from experimental inhalation anthrax.
abstract: BACKGROUND
  Anthrax represents a formidable bioterrorism threat for which new, optimized vaccines are required. We previously demonstrated that epitope-focused multiple antigenic peptides or a recombinant protein in Freund's adjuvant can elicit Ab against the loop neutralizing determinant (LND), a cryptic linear neutralizing epitope in the 2ß2-2ß3 loop of protective antigen from Bacillus anthracis, which mediated protection of rabbits from inhalation challenge with B. anthracis Ames strain. However, demonstration of efficacy using human-use adjuvants is required before proceeding with further development of an LND vaccine for testing in non-human primates and humans.
  
  
  METHODS
  To optimize the LND immunogen, we first evaluated the protective efficacy and immune correlates associated with immunization of rabbits with mixtures containing two molecular variants of multiple antigenic peptides in Freunds adjuvant, termed BT-LND(2) and TB-LND(2). TB-LND(2) was then further evaluated for protective efficacy in rabbits employing human-use adjuvants.
  
  
  RESULTS
  Immunization of rabbits with TB-LND(2) in human-use adjuvants elicited protection from Ames strain spore challenge which was statistically indistinguishable from that elicited through immunization with protective antigen. All TB-LND(2) rabbits with any detectable serum neutralization prior to challenge were protected from aerosolized spore exposure. Remarkably, rabbits immunized with TB-LND(2) in Alhydrogel/CpG had significant anamnestic increases in post-challenge LND-specific Ab and neutralization titers despite little evidence of spore germination in these rabbits.
  
  
  CONCLUSIONS
  An LND-specific epitope-focused vaccine may complement PA-based vaccines and may represent a complementary stand-alone vaccine for anthrax.
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA; Veterans Administration Ann Arbor Healthcare System, 2215 Fuller Road, Ann Arbor, MI 48105, USA. Electronic address: joscher@umich.edu.
authors.forename: Jon
authors.initials: J
authors.lastname: Oscherwitz
authors.affiliation: University of Michigan Medical School, Ann Arbor, MI 48105, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Feldman
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
authors.forename: Fen
authors.initials: F
authors.lastname: Yu
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA; Veterans Administration Ann Arbor Healthcare System, 2215 Fuller Road, Ann Arbor, MI 48105, USA.
authors.forename: Kemp B
authors.initials: KB
authors.lastname: Cease
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000536:Aluminum Hydroxide / Q000008:administration & dosage; D000818:Animals; D000881:Anthrax / Q000276:immunology / Q000517:prevention & control*; D022122:Anthrax Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D001427:Bacterial Toxins / Q000276:immunology*; D004195:Disease Models, Animal; D000939:Epitopes / Q000276:immunology*; D005260:Female; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage; D011817:Rabbits; D012141:Respiratory Tract Infections / Q000276:immunology / Q000517:prevention & control*; D016896:Treatment Outcome; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D022122:Anthrax Vaccines; D000942:Antigens, Bacterial; D001427:Bacterial Toxins; C408982:CPG-oligonucleotide; D000939:Epitopes; D009838:Oligodeoxyribonucleotides; D014614:Vaccines, Synthetic; C030325:anthrax toxin; D000536:Aluminum Hydroxide
keywords: Antibody; Epitope; Inhalation anthrax; Neutralization; Peptide; Vaccine