An index of blood neutrophil injury in man and animals immunized with live anthrax vaccine]

The authors present the results of study of the blood neutrophil injury in guinea pigs, rabbits, monkeys, and also humans inoculated subcutaneously with live anthrax vaccine. Along with intradermal test with anthraxin, the mentioned test is suggested to assess the immunological status of persons immunized with anthrax vaccine.     

Preventing voltage-dependent gating of anthrax toxin channels using engineered disulfides

The channel-forming component of anthrax toxin, (PA₆₃)₇, is a heptameric water-soluble protein at neutral pH, but under acidic conditions it spontaneously inserts into lipid bilayers to form a 14-stranded β-barrel ion-conducting channel. This channel plays a vital role in anthrax pathogenesis because it serves as a conduit for the membrane translocation of the two enzymatic components of anthrax toxin, lethal factor and edema factor. Anthrax channels open and close in response to changes in transmembrane voltage, a property shared by several other pore-forming toxins. We have discovered an unexpected phenomenon in cysteine-substituted channels that provides a window into this gating process: their normal voltage-dependent gating can be abolished by reaction with methanethiosulfonate (MTS) reagents or exposure to oxidizing conditions. Remarkably, this perturbation is seen with cysteines substituted at sites all along the ~100 Å length of the channel's β-barrel. In contrast, reaction with N-ethylmaleimide, a thiol-reactive compound that does not form a mixed disulfide, does not affect gating at any of the sites tested. These findings, coupled with our biochemical detection of dimers, have led us to conclude that MTS reagents are catalyzing the formation of intersubunit disulfide bonds that lock channels in a conducting state, and that voltage gating requires a conformational change that involves the entire β-barrel.     

Hereditary resistance to anthrax and sensitivity to the anthrax toxin in mice

The degree of the hereditary susceptibility of mice to anthrax caused by noncapsular and capsule-forming Bacillus anthracis strains has been found to be directly related to the sensitivity of the animals to the edematogenic and immunosuppressing action of anthrax toxin. The genetic analysis indicates that resistance to anthrax is probably controlled by a dominant gene, not linked with histocompatibility complex H-2 and, probably, unrelated to the presence of hemolytic activity in mouse sera, determined by component C5 of the complement.     

Specific intoxication in anthrax infection

The pathomorphological picture of experimental B. anthracis infection in white rats (strain Fisher-344) essentially corresponds to experimental anthracic intoxication with very moderately pronounced morphological manifestation of B. anthracis invasion. This indicates that specific anthracic intoxication is an essential component of the pathological process in B. anthracis infection.