Boosting cell-intrinsic innate immune recognition of HIV-1 by dendritic cells

描述（由申请人提供）：2011年有250万人感染了HIV-1。显然，我们需要一种预防HIV-1感染的疫苗。然而，对HIV-1的免疫反应与对天花等其他病毒的免疫反应有着根本的不同，目前已经开发出了有效的疫苗。面对记录的HIV-1特异性体液和细胞免疫反应，HIV-1感染者进展为艾滋病，甚至可能继发感染HIV-1。如果在了解抗HIV-1免疫的基础上不对疫苗设计进行重大修改，即使是活疫苗也无法预防HIV-1感染。健忘的抗病毒反应，包括细胞毒性T淋巴细胞和中和抗体，需要由成熟到足以产生一系列信号和因子（包括IL-12）的dc启动naïve抗原特异性T细胞。当模式识别受体（PRRs）在呈现病毒抗原的相同dc内被激活时，这种成熟对于启动抗病毒反应是最理想的（内在检测）。HIV-1进入常规抗原呈递dc的主要途径允许有效的HIV-1抗原呈递，但阻碍成熟：不发生逆转录，不激活PRRs，不产生1型干扰素。在没有DC成熟的情况下，T细胞启动为描述良好的无效抗hiv -1免疫反应提供了解释。为了最大限度地使DC成熟并改善HIV-1特异性T细胞启动的结果，本文提出的实验将增加呈递HIV-1抗原的相同DC内PRRs对HIV-1的内在识别。这将通过VSV糖蛋白伪分型将HIV-1重定向到有效的dc进入途径，并利用最近关于dc内HIV-1先天免疫感知的发现来实现：trim5介导的NF-κB和c-Jun信号将通过对HIV-1衣壳的工程修饰在dc中激活；通过阻断三磷酸水解酶SAMHD1，将允许dc中新生的HIV-1逆转录；DC核酸酶TREX1和RNASEH2的破坏将允许HIV-1逆转录物积累到激活1型IFN的水平；诸如cGAS之类的PRRs将由HIV-1自身传递，以放大先天免疫信号。将确定这些干预措施的组合，使dc成熟到最佳地启动抗HIV-1特异性CD4+和CD8+ T细胞反应，这些条件将用于免疫最先进的人源化小鼠，其中我们已经检测到HIV-1株特异性中和抗体。这些实验将确定dc对HIV-1的内在感知是否会改善对HIV-1的获得性免疫反应，如果确实如此，将为开发人类有效的抗HIV-1疫苗提供路线图。

DESCRIPTION (provided by applicant): 2.5 million people became infected with HIV-1 in 2011. Clearly, a vaccine that prevents HIV-1 infection is needed. The immune response to HIV-1, though, differs fundamentally from that of other viruses such as smallpox for which effective vaccines have been developed. In the face of documented HIV-1-specific humoral and cellular immune responses, HIV-1-infected people progress to AIDS and can even be secondarily infected with HIV-1. Without critical modifications to vaccine design based on understanding of anti-HIV-1 immunity, even a live-vaccine would not prevent HIV-1 infection. Anamnestic, antiviral responses, including cytotoxic T lymphocytes and neutralizing antibodies, require priming of naïve, antigen-specific T cells by DCs that have matured sufficiently to produce an array of signals and factors, including IL-12. Such maturation is optimal for priming antiviral responses when pattern recognition receptors (PRRs) are activated within the same DCs that present viral antigen (intrinsic detection). The dominant pathway by which HIV-1 enters conventional, antigen-presenting DCs permits efficient HIV-1 antigen presentation but precludes maturation: reverse transcription does not occur, PRRs are not activated, and type 1 interferon is not produced. T cell priming in the absence of DC maturation provides an explanation for well-described, ineffective anti-HIV-1 immune responses. To maximize DC maturation and improve the outcome of HIV-1-specific T cell priming, the experiments proposed here will increase intrinsic recognition of HIV-1 by PRRs within the same DCs that present HIV-1 antigen. This will be done by redirecting HIV-1 to a productive DC-entry pathway by pseudo-typing with VSV Glycoprotein and exploiting recent discoveries concerning innate immune sensing of HIV-1 within DCs: TRIM5-mediated NF-κB and c-Jun signaling will be activated in DCs by engineered modifications in the HIV-1 capsid; nascent HIV-1 reverse transcription in DCs will be permitted by blocking the triphosphohydrolase SAMHD1; disruption of DC nucleases TREX1 and RNASEH2 will permit HIV-1 reverse transcripts to accumulate to levels that activate type 1 IFN; PRRs such as cGAS will be delivered by HIV-1 itself in order to amplify innate immune signaling. The combination of these interventions that matures DCs to optimally prime anti-HIV-1-specific CD4+ and CD8+ T cell responses will be identified and these conditions will be used to immunize state-of-the-art, humanized mice, in which we have already detected HIV-1 strain-specific neutralizing antibodies. These experiments will determine if intrinsic sensing of HIV-1 by DCs improves acquired immune responses to HIV-1 and, if it does, offer a roadmap for the development of potent, anti-HIV-1 vaccines in people.