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

描述(申请人提供)：2011年有250万人感染了HIV-1。显然，需要一种预防艾滋病毒-1感染的疫苗。然而，对HIV-1的免疫反应与天花等其他病毒的免疫反应根本不同，这些病毒已经开发出有效的疫苗。面对记录在案的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。如果不根据对抗HIV-1免疫的理解对疫苗设计进行关键修改，即使是活疫苗也无法预防HIV-1感染。回忆、抗病毒反应，包括细胞毒性T淋巴细胞和中和抗体，需要DC启动幼稚的、抗原特异性的T细胞，这些DC已经足够成熟，可以产生一系列信号和因子，包括IL-12。当模式识别受体(PRR)在呈递病毒抗原的同一树突状细胞(内在检测)中被激活时，这种成熟对于启动抗病毒反应是最佳的。HIV-1进入传统的抗原提呈树突状细胞的主要途径是允许有效的HIV-1抗原提呈，但阻止成熟：不发生逆转录，不激活PRR，不产生1型干扰素。T细胞在缺乏DC成熟的情况下启动，为人们所熟知的、无效的抗HIV-1免疫反应提供了一种解释。为了最大限度地促进树突状细胞的成熟，并改善HIV-1特异性T细胞预置的结果，这里提出的实验将在呈现HIV-1抗原的相同DC内增加PRRs对HIV-1的内在识别。要做到这一点，将通过与VSV糖蛋白伪分型将艾滋病毒-1重定向到有效的DC进入途径，并利用关于DC内艾滋病毒-1的天然免疫感应的最新发现：TRIM5介导的NF-κB和c-jun信号将通过对艾滋病毒-1衣壳的工程修饰在DC中被激活；通过阻断三磷水解酶SAMHD1，将允许在DC中新生的艾滋病毒-1反转录；DC核酸酶TREX1和RNaseH2的破坏将允许艾滋病毒-1逆转录本积累到激活1型干扰素的水平；PRR，如cGAS，将由艾滋病毒-1自身传递，以便放大天然免疫信号。将确定这些干预措施的组合，使DC成熟以最佳地启动抗HIV-1特异性CD4和CD8 T细胞反应，并将这些条件用于免疫最先进的人源化小鼠，我们已经在其中检测到HIV-1毒株特异性中和抗体。这些实验将确定DC对HIV-1的内在感知是否改善了对HIV-1的获得性免疫反应，如果是的话，将为在人类中开发有效的抗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.