Protection against anthrax by needle-free mucosal immunization with human anthrax vaccine

Abstract

Human vaccination with BioThrax™ requires six injections followed by annual boosters. This makes it difficult for the compliance of the immunization program and underscores the need for development of a new and optimized vaccination protocol. Current research aims to demonstrate the proof of concept to develop a needle free mucosal immunization protocol using a murine anthrax model. A/ J mice were immunized with BioThrax™ via an intranasal route. Sera, saliva, vaginal, and nasal washes were evaluated for protective antigen (PA) specific antibody responses by ELISA. Antigenspecific, antibody-secreting lymphocytes were measured by ELISPOT. Sera neutralization antibody titers were determined by in vitro anthrax lethal toxin (Letx) neutralization assay. Immunized animals were challenged by a lethal dose of Bacillus anthracis Sterne spores to determine the efficacy of the vaccination. Nasal mucosal immunization with BioThrax™ elicited robust serum and mucosal antibody responses against PA. The antigen specific antibodies neutralized anthrax Letx, as demonstrated by in vitro neutralization assays. Two doses of intranasal BioThrax™ were sufficient to completely protect A/J mice against challenge with 100×LD 50 Bacillus anthracis Sterne spores. The data suggests that intranasal administration may be an effective immunization modality for an improved immunization program against anthrax.

Targeted Silencing of Anthrax Toxin Receptors Protects against Anthrax Toxins

“…Some cells were incubated with 100 l/well PBS instead of LeTx and were used as viable cell control samples. Following toxin treatments, a thiazolyl blue tetrazolium bromide (MTT) colorimet- ric assay was used to assess cell viability as described previously (12)(13)(14)(15), with some modification. Briefly, 20 l of MTT was added to each well and incubated for 2 h at 37°C and 5% CO 2 .…”

Expression of either Lethal Toxin or Edema Toxin by Bacillus anthracis Is Sufficient for Virulence in a Rabbit Model of Inhalational Anthrax

“…An alternative mouse model to evaluate antitoxin therapeutics would be to use the complement C5-deficient, A/J or DBA/2, mouse strains. These mouse strains are protected against inhalational anthrax by vaccination with rPA or AVA (77,81), and lethal toxin was shown to be required for systemic bacterial dissemination and death (38). However, these models require using the acapsular, avirulent Sterne strain of B. anthracis.…”

Protective immunity against botulism provided by a single dose vaccination with an adenovirus-vectored vaccine

“…The color reaction was terminated by adding 100 μl 0.5 M EDTA and the absorbance values were obtained using a Dynatech MR4000 model microplate reader at 405 nm. A standard curve was generated for each set of samples and serum antibody concentrations were calculated in accordance with a standard curve as previously described [32].…”