Biophysical characterization and immunization studies of dominant negative inhibitor (DNI), a candidate anthrax toxin subunit vaccine

Hum Vaccin Immunother. 2013 Nov;9(11):2362-70. doi: 10.4161/hv.25852. Epub 2013 Aug 7.


Dominant Negative Inhibitor (DNI) is a translocation-deficient homolog of recombinant protective antigen of Bacillus anthracis that is a candidate for a next generation anthrax vaccine. This study demonstrates that the biophysical characteristics of the DNI protein stored in lyophilized form at 4°C for 8 y were similar to recombinant Protective Antigen (rPA). To provide information on the accelerated stability of DNI, samples in the lyophilized form were subjected to thermal stress (40°C and 70°C for up to 4 weeks) and thoroughly evaluated using various biophysical and chemical characterization techniques. Results demonstrate preserved structural stability of the DNI protein under extreme conditions, suggesting long-term stability can be achieved for a vaccine that employs DNI, as desired for a biodefense countermeasure. Furthermore, the biological activity of the stressed DNI bound to the adjuvant Alhydrogel (®) was evaluated in mice and it was found that the immunogenicity DNI was not affected by thermal stress.

Keywords: Accelerated Stability; Aluminum Hydroxide; Biophysical characterization; Dominant-Negative Inhibitor; Immunogenicity; Vaccine.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adjuvants, Immunologic / administration & dosage
  • Aluminum Hydroxide / administration & dosage
  • Animals
  • Anthrax / prevention & control*
  • Anthrax Vaccines / administration & dosage
  • Anthrax Vaccines / immunology*
  • Antigens, Bacterial / chemistry*
  • Antigens, Bacterial / immunology*
  • Bacillus anthracis / immunology*
  • Bacterial Toxins / chemistry*
  • Bacterial Toxins / immunology*
  • Biophysical Phenomena
  • Drug Stability
  • Freeze Drying
  • Immunization / methods*
  • Mice, Inbred BALB C
  • Protein Conformation
  • Protein Stability / radiation effects
  • Protein Subunits / chemistry
  • Protein Subunits / immunology
  • Temperature
  • Vaccines, Subunit / administration & dosage
  • Vaccines, Subunit / immunology


  • Adjuvants, Immunologic
  • Anthrax Vaccines
  • Antigens, Bacterial
  • Bacterial Toxins
  • Protein Subunits
  • Vaccines, Subunit
  • anthrax toxin
  • Aluminum Hydroxide