Efficacy of recombinant anthrax vaccine against Bacillus anthracis aerosol spore challenge: preclinical evaluation in rabbits and Rhesus monkeys.

This report describes the immunogenicity and protective efficacy of Escherichia coli-expressed recombinant protective antigen (rPA) in New Zealand White rabbits and Rhesus Macaques against an aerosol challenge with Bacillus anthracis spores (IVRI strain, tox+cap+). A dose-ranging study was performed in which it became evident that the level of anti-PA IgG and toxin-neutralizing antibody titer was directly proportional to the dose of rPA administered. However, the onset time of primary and secondary immune response was not dependent on the dosage.

Genetic immunization with GPI-anchored anthrax protective antigen raises combined CD1d- and MHC II-restricted antibody responses by natural killer T cell-mediated help.

Studies have demonstrated that lipid rafts ultimately regulate the endocytosis of anthrax toxin via clathrin dependent pathway. Interestingly, GPI-anchored protein rich rafts have also been shown to be transported down to the endocytic pathway to reducing late endosomes. Taking advantage of this parallelism, we tried translating the anthrax toxin natural intoxication mechanism by administering a DNA chimera that encoded protective antigen attached to a mammalian GPI-anchor sequence at its C-terminus (pGPI-PA63).

Anthrax protective antigen administered by DNA vaccination to distinct subcellular locations potentiates humoral and cellular immune responses.

Based on the hypothesis that immune outcome can be influenced by the form of antigen administered and its ability to access various antigen-processing pathways, we targeted the 63 kDa fragment of protective antigen (PA) of Bacillus anthracis to various subcellular locations by DNA chimeras bearing a set of signal sequences. These targeting signals, namely, lysosome-associated membrane protein 1 (LAMP1), tissue plasminogen activator (TPA) and ubiquitin, encoded various forms of PA viz. lysosomal, secreted and cytosolic, respectively.

Oral vaccines: new needs, new possibilities.

Vaccination is an important tool for handling healthcare programs both in developed and developing countries. The current global scenario calls for a more-efficacious, acceptable, cost-effective and reliable method of immunization for many fatal diseases. It is hoped that the adoption of oral vaccines will help to provide an effective vaccination strategy, especially in developing countries.

Induction of cytotoxic T lymphocyte response against Mycobacterial antigen using domain I of anthrax edema factor as antigen delivery system.

We have investigated the efficiency of N-terminal 1-260 residues of Edema factor (EFn) as a delivery system for ESAT-6, an antigenic protein of Mycobacterium tuberculosis H(37)R(v), into the cytosol of mammalian cells. The EFn.ESAT-6 recombinant protein was obtained by genetic fusion of EFn and ESAT-6 DNA.

Evaluation of the ability of N-terminal fragment of lethal factor of Bacillus anthracis for delivery of Mycobacterium T cell antigen ESAT-6 into cytosol of antigen presenting cells to elicit effective cytotoxic T lymphocyte response.

We report the ability of N-terminal fragment of lethal factor of Bacillus anthracis to deliver genetically fused ESAT-6 (early secretory antigen target), a potent T cell antigen of Mycobacterium tuberculosis, into cytosol to elicit Cytotoxic T lymphocyte (CTL) response. In vitro Th1 cytokines data and CTL assay proved that efficient delivery of LFn.ESAT-6 occurs in cytosol, in the presence of protective antigen (PA), and leads to generation of effective CTL response.

Cloning, expression, and characterization of recombinant nitric oxide synthase-like protein from Bacillus anthracis.

Nitric oxide synthase (NOS) is amongst a family of evolutionarily conserved enzymes, involved in a multi-turnover process that results in NO as a product. The significant role of NO in various pathological and physiological processes has created an interest in this enzyme from several perspectives. This study describes for the first time, cloning and expression of a NOS-like protein, baNOS, from Bacillus anthracis, a pathogenic bacterium responsible for causing anthrax.