Endosomal Toll-Like Receptors 7 and 9 Cooperate in Detection of Murine Gammaherpesvirus 68 Infection
Endosomal Toll-Like Receptors 7 and 9 Cooperate in Detection of Murine Gammaherpesvirus 68 Infection
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DOI：
10.1128/jvi.01173-18
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发表时间：
2019-02-01
影响因子：
5.4
通讯作者：
Brinkmann, Melanie M.
中科院分区：
文献类型：
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作者：
Bussey, Kendra A.;Murthy, Sripriya;Brinkmann, Melanie M.
鼠γ疱疹病毒68（MHV 68）是一种适用于研究人类病原体EB病毒和卡波西肉瘤相关疱疹病毒的小动物模型。在这里，我们已经表征了内体Toll样受体（TLR）护送蛋白UNC 93 B，内体TLR 7，-9和-13，以及细胞表面TLR 2在MHV 68检测中的作用。我们发现，与野生型（WT）细胞中的水平相比，浆细胞样树突状细胞（pDC）对MHV 68的α干扰素（IFN-α）应答在Tlr 9（-/-）细胞中降低，但未完全丧失。Tlr 7（-/-）pDC与WT类似地响应。然而，我们发现在Unc 93 b（-/-）pDC中，以及在Tlr 7（-/-）Tlr 9（-/-）双敲除pDC中，IFN-α对MHV 68的应答被完全消除。因此，对pDC中IFN-α对MHV 68的应答有贡献的模式识别受体仅有TLR 7和TLR 9，但TLR 7的贡献被TLR 9的存在掩盖。为了研究UNC 93 B和TLR在体内MHV 68感染中的作用，我们用MHV 68感染小鼠。静脉内感染后，在UNC 93 B缺陷小鼠的肺、脾和肝、TLR 9缺陷小鼠的脾以及Tlr 7（-/-）Tlr 9（-/-）小鼠的肝和脾中，MHV 68的裂解复制增强。TLR 2或TLR 13的缺乏不影响裂解病毒滴度。然后，我们比较了来自潜伏感染的WT、Unc 93 b（-/-）、Tlr 7（-/-）、Tlr 9（-/-）、Tlr 7（-/-）和Tlr 9（-/-）脾细胞的MHV 68的再活化。我们观察到增强的再活化和潜伏病毒载量，特别是与WT中的水平相比来自Tlr 7（-/-）Tlr 9（-/-）脾细胞。我们的数据表明，UNC 93 B依赖性TLR 7和TLR 9合作，并有助于检测和控制MHV 68 infection.Importance的两个人类γ疱疹病毒，EB病毒（EBV）和卡波西肉瘤相关疱疹病毒（KSHV），可以导致侵略性形式的癌症。这些疱疹病毒是严格的宿主特异性，因此同源鼠γ疱疹病毒68（MHV 68）是一种广泛使用的模型，以获得体内的见解，这两个γ疱疹病毒和它们的主机之间的相互作用。与EBV和KSHV一样，MHV 68在B细胞中建立终身潜伏期。先天性免疫系统作为宿主防御的第一道防线之一，其中模式识别受体如Toll样受体在对各种病原体产生有效的抗病毒免疫应答中起着至关重要的作用。在这里，我们揭示了Toll样受体7在一个称为浆细胞样树突状细胞的免疫细胞亚群中识别MHV 68的尚未预料到的作用，以及对宿主中这种病毒的控制。
Murine gammaherpesvirus 68 (MHV68) is a small-animal model suitable for study of the human pathogens Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. Here, we have characterized the roles of the endosomal Toll-like receptor (TLR) escort protein UNC93B, endosomal TLR7, -9, and -13, and cell surface TLR2 in MHV68 detection. We found that the alpha interferon (IFN-alpha) response of plasmacytoid dendritic cells (pDC) to MHV68 was reduced in Tlr9(-/-) cells compared to levels in wild type (WT) cells but not completely lost. Tlr7(-/-) pDC responded similarly to WT. However, we found that in Unc93b(-/-) pDC, as well as in Tlr7(-/-) Tlr9(-/-) double-knockout pDC, the IFN-alpha response to MHV68 was completely abolished. Thus, the only pattern recognition receptors contributing to the IFN-alpha response to MHV68 in pDC are TLR7 and TLR9, but the contribution of TLR7 is masked by the presence of TLR9. To address the role of UNC93B and TLR for MHV68 infection in vivo, we infected mice with MHV68. Lytic replication of MHV68 after intravenous infection was enhanced in the lungs, spleen, and liver of UNC93B-deficient mice, in the spleen of TLR9-deficient mice, and in the liver and spleen of Tlr7(-/-) Tlr9(-/-) mice. The absence of TLR2 or TLR13 did not affect lytic viral titers. We then compared reactivation of MHV68 from latently infected WT, Unc93b(-/-), Tlr7(-/-), Tlr9(-/-), Tlr7(-/-), and Tlr9(-/-) splenocytes. We observed enhanced reactivation and latent viral loads, particularly from Tlr7(-/-) Tlr9(-/-) splenocytes compared to levels in the WT. Our data show that UNC93B-dependent TLR7 and TLR9 cooperate in and contribute to detection and control of MHV68 infection.IMPORTANCE The two human gammaherpesviruses, Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), can cause aggressive forms of cancer. These herpesviruses are strictly host specific, and therefore the homolog murine gammaherpesvirus 68 (MHV68) is a widely used model to obtain in vivo insights into the interaction between these two gammaherpesviruses and their host. Like EBV and KSHV, MHV68 establishes lifelong latency in B cells. The innate immune system serves as one of the first lines of host defense, with pattern recognition receptors such as the Toll-like receptors playing a crucial role in mounting a potent antiviral immune response to various pathogens. Here, we shed light on a yet unanticipated role of Toll-like receptor 7 in the recognition of MHV68 in a subset of immune cells called plasmacytoid dendritic cells, as well as on the control of this virus in its host.