Bordetella pertussis adenylate cyclase toxin modulates innate and adaptive immune responses:: Distinct roles for acylation and enzymatic activity in immunomodulation and cell death
Bordetella pertussis adenylate cyclase toxin modulates innate and adaptive immune responses:: Distinct roles for acylation and enzymatic activity in immunomodulation and cell death
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DOI：
10.4049/jimmunol.175.2.730
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发表时间：
2005-07-15
影响因子：
4.4
通讯作者：
Mills, KHG
中科院分区：
文献类型：
--
作者：
Boyd, AP;Ross, PJ;Mills, KHG
百日咳杆菌的腺苷环化酶毒素(CyaA)属于致孔毒素家族中的重复序列，需要翻译后的酰化作用才能裂解真核细胞。CyaA在内毒素刺激下调节树突状细胞和巨噬细胞的功能。在这项研究中，我们研究了酰化作用和酶活性在CyaA的免疫调节和裂解作用中的作用。CyaA的腺苷环化酶活性是其对小鼠天然免疫细胞调节作用所必需的。相反，酰化不是细胞色素A免疫调节功能所必需的，而是最大限度激活caspase-3和细胞毒活性所必需的。野生型酰化毒素(A-CyaA)和非酰化CyaA(NA-CyaA)可增强TLR配体诱导的IL-10，抑制巨噬细胞和DC产生IL-12、TNF-α和CCL3。此外，A-CyaA和NA-CyaA均可促进未成熟DC表面CD80的表达，而CpG刺激的CD40和ICAM-1的表达均低于未成熟DC。此外，A-CyaA和NA-CyaA在体内都能促进诱导小鼠IgG1Abs、Th2和调节性T细胞对抗联合给药的AGS，而IAC-CyaA的佐剂活性更有限。相反，A-CyaA和IAC-CyaA可诱导巨噬细胞caspase-3激活和细胞死亡，但NA-CyaA可显著降低或不影响这些作用。我们的发现表明，酶活性在CyaA的免疫调节作用中起着关键作用，而酰化作用有助于诱导细胞凋亡和细胞溶解，因此，NA-CyaA具有相当大的潜力作为一种无毒的治疗分子，具有强大的抗炎特性。
Adenylate cyclase toxin (CyaA) of Bordetella pertussis belongs to the repeat in toxin family of pore-forming toxins, which require posttranslational acylation to lyse eukaryotic cells. CyaA modulates dendritic cell (DC) and macrophage function upon stimulation with LPS. In this study, we examined the roles of acylation and enzymatic activity in the immunomodulatory and lytic effects of CyaA. The adenylate cyclase activity of CyaA was necessary for its modulatory effects on murine innate immune cells. In contrast, acylation was not essential for the immunomodulatory function of CyaA, but was required for maximal caspase-3 activation and cytotoxic activity. The wild-type acylated toxin (A-CyaA) and nonacylated CyaA (NA-CyaA), but not CyaA with an inactive adenylate cyclase domain (iAC-CyaA), enhanced TLR-ligand-induced IL-10 and inhibited IL-12, TNF-alpha, and CCL3 production by macrophages and DC. In addition, both A-CyaA and NA-CyaA, but not iAC-CyaA, enhanced surface expression of CD80 and decreased CpG-stimulated CD40 and ICAM-1 expression on immature DC. Furthermore, both A-CyaA and NA-CyaA promoted the induction of murine IgG1 Abs, Th2, and regulatory T cells against coadministered Ags in vivo, whereas iAC-CyaA had more limited adjuvant activity. In contrast, A-CyaA and iAC-CyaA induced caspase-3 activation and cell death in macrophages, but these effects were considerably reduced or absent with NA-CyaA. Our findings demonstrate that the enzymatic activity plays a critical role in the immunomodulatory effects of CyaA, whereas acylation facilitates the induction of apoptosis and cell lysis, and as such, NA-CyaA has considerable potential as a nontoxic therapeutic molecule with potent anti-inflammatory properties.