Tolerance and Cross-Tolerance following Toll-Like Receptor (TLR)-4 and -9 Activation Are Mediated by IRAK-M and Modulated by IL-7 in Murine Splenocytes.
Tolerance and Cross-Tolerance following Toll-Like Receptor (TLR)-4 and -9 Activation Are Mediated by IRAK-M and Modulated by IL-7 in Murine Splenocytes.
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DOI：
10.1371/journal.pone.0132921
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Crouser ED
中科院分区：
文献类型：
--
作者：
Julian MW;Strange HR;Ballinger MN;Hotchkiss RS;Papenfuss TL;Crouser ED
重症期间的免疫抑制易导致严重感染。我们试图在一个重现完整的体内免疫反应的模型中确定调节对常见促炎危险信号的耐受性和交叉耐受性的机制。将从野生型或匹配的IRAK-M敲除（IRAK-M-/-）C57 BL/6雄性小鼠（8-10周龄）获得的Flt 3扩增的脾细胞分别用LPS或CpGA DNA（Toll样受体（TLR）-4和-9的激动剂）在连续24小时内重复或交替处理。在每个24小时周期后收集上清液，测定细胞因子释放（ELISA）和脾细胞IRAK-M表达（Western印迹）。在不存在或存在程序性死亡受体（PD）-1阻断抗体或IL-7预处理的情况下评估耐受性和交叉耐受性。脾细胞对随后用LPS或CpGA DNA处理显着表现出耐受性和交叉耐受性。在该模型中，在初始LPS或CpGA处理后，耐受和交叉耐受的特征是明显的，因为LPS后TNFα和IFNγ（而不是IL-10）的释放被抑制;而初始CpGA处理抑制了对随后刺激（LPS或CpGA）的响应的TNFα、IFNγ和IL-10的释放。耐受性和交叉耐受性与IL-10释放或PD-1无关，但在IRAK-M-/-脾细胞中减弱。IL-7显著抑制IRAK-M表达并恢复TNFα和IFNγ的产生，而不影响IL-10的释放。总之，响应于LPS或CpGA的急性免疫耐受和交叉耐受是不同的，因为LPS选择性地抑制促炎细胞因子反应;而CpGA抑制促炎和抗炎反应。响应于常见危险信号的耐受性和交叉耐受性的诱导在机制上与IL-10或PD-1无关，但受到IRAK-M表达的直接影响。IL-7降低IRAK-M表达并减弱LPS或CpGA诱导的免疫耐受，因此可用于逆转危重病背景下的免疫耐受。
Immune suppression during critical illness predisposes to serious infections. We sought to determine the mechanisms regulating tolerance and cross-tolerance to common pro-inflammatory danger signals in a model that recapitulates the intact in vivo immune response. Flt3-expanded splenocytes obtained from wild-type or matching IRAK-M knockout (IRAK-M-/-), C57BL/6, male mice (8–10 weeks old) were treated repeatedly or alternately with either LPS or CpGA DNA, agonists of Toll-like receptor (TLR)-4 and -9, respectively, over successive 24-hour periods. Supernatants were collected following each 24-hour period with cytokine release (ELISA) and splenocyte IRAK-M expression (Western blot) determined. Tolerance and cross-tolerance were assessed in the absence or presence of programmed death receptor (PD)-1 blocking antibody or IL-7 pre-treatment. Splenocytes notably exhibited both tolerance and cross-tolerance to subsequent treatments with either LPS or CpGA DNA. The character of tolerance and cross-tolerance in this model was distinct following initial LPS or CpGA treatment in that TNFα and IFNγ release (not IL-10) were suppressed following LPS; whereas, initial CpGA treatment suppressed TNFα, IFNγ and IL-10 release in response to subsequent stimulation (LPS or CpGA). Tolerance and cross-tolerance were unrelated to IL-10 release or PD-1 but were attenuated in IRAK-M-/- splenocytes. IL-7 significantly suppressed IRAK-M expression and restored TNFα and IFNγ production without influencing IL-10 release. In summary, acute immune tolerance and cross-tolerance in response to LPS or CpGA were distinct in that LPS selectively suppressed pro-inflammatory cytokine responses; whereas, CpGA suppressed both pro- and anti-inflammatory responses. The induction of tolerance and cross-tolerance in response to common danger signals was mechanistically unrelated to IL-10 or PD-1 but was directly influenced by IRAK-M expression. IL-7 reduced IRAK-M expression and attenuated immune tolerance induced by either LPS or CpGA, and thus may be useful for reversal of immune tolerance in the setting of critical illness.