Association of Bacillus anthracis Capsule with Lethal Toxin during Experimental Infection
Association of Bacillus anthracis Capsule with Lethal Toxin during Experimental Infection
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DOI：
10.1128/iai.00764-08
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发表时间：
2009-02-01
影响因子：
3.1
通讯作者：
Ribot, W. J.
中科院分区：
文献类型：
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作者：
Ezzell, J. W.;Abshire, T. G.;Ribot, W. J.
在感染的非洲绿猴、兔和豚鼠的血浆中发现了炭疽芽孢杆菌致死毒素(LT)。在所有病例中，在感染的末期，只在血浆中检测到蛋白酶激活的63 kDa形式的保护性抗原(PA(63))和残留的20 kDa片段(PA(20))。在感染末期，中毒动物的血浆中未检测到分子量为83 kDa的未切割PA。PA(63)与致死因子(LF)密切相关，形成LT。通过Western blotting、捕获酶联免疫吸附试验和大小排斥层析对LT进行了表征，结果表明炭疽杆菌释放的抗吞噬多聚γ-D-谷氨酸(Gamma-DPGA)胶囊与动物血液中LT有不同程度的结合。虽然这种体内关联的性质尚不清楚，但我们能够确定这些LT/Gamma-DPGA复合体中的一部分保留了LF蛋白水解酶活性。我们的发现表明，体内LT复合体不同于体外产生的LT，在体外检测LT对特定免疫细胞的影响时，包括Gamma-DPGA可能揭示Gamma-DPGA在炭疽发病中的新的和重要的作用。
Bacillus anthracis lethal toxin ( LT) was characterized in plasma from infected African Green monkeys, rabbits, and guinea pigs. In all cases, during the terminal phase of infection only the protease-activated 63-kDa form of protective antigen (PA(63)) and the residual 20-kDa fragment (PA(20)) were detected in the plasma. No uncut PA with a molecular mass of 83 kDa was detected in plasma from toxemic animals during the terminal stage of infection. PA(63) was largely associated with lethal factor (LF), forming LT. Characterization of LT by Western blotting, capture enzyme-linked immunosorbent assay, and size exclusion chromatography revealed that the antiphagocytic poly-gamma-D-glutamic acid (gamma-DPGA) capsule released from B. anthracis bacilli was associated with LT in animal blood in variable amounts. While the nature of this in vivo association is not understood, we were able to determine that a portion of these LT/gamma-DPGA complexes retained LF protease activity. Our findings suggest that the in vivo LT complexes differ from in vitro-produced LT and that including gamma-DPGA when examining the effects of LT on specific immune cells in vitro may reveal novel and important roles for gamma-DPGA in anthrax pathogenesis.