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，需要预防HIV-1感染的疫苗。然而，对HIV-1的免疫反应与其他病毒（如天花）的免疫反应根本不同，天花已经开发出了有效的疫苗。面对记录在案的HIV-1特异性体液和细胞免疫应答，HIV-1感染者进展为AIDS，甚至可能继发HIV-1感染。如果不根据对抗HIV-1免疫的理解对疫苗设计进行关键性修改，即使是活疫苗也无法预防HIV-1感染。回忆性抗病毒反应，包括细胞毒性T淋巴细胞和中和抗体，需要通过DC引发幼稚的抗原特异性T细胞，这些DC已经成熟到足以产生一系列信号和因子，包括IL-12。当模式识别受体（PRR）在呈递病毒抗原的相同DC内被激活时（内在检测），这种成熟对于引发抗病毒应答是最佳的。HIV-1进入常规的抗原呈递DC的主要途径允许有效的HIV-1抗原呈递，但阻止成熟：逆转录不发生，PRR不被激活，1型干扰素不产生。在缺乏DC成熟的情况下的T细胞引发为充分描述的无效的抗HIV-1免疫应答提供了解释。为了使DC成熟最大化并改善HIV-1特异性T细胞引发的结果，本文提出的实验将增加呈递HIV-1抗原的相同DC内的PRR对HIV-1的内在识别。这将通过用VSV糖蛋白假型化将HIV-1重定向到生产性DC进入途径并利用关于DC内HIV-1的先天免疫感应的最新发现来完成：TRIM 5介导的NF-κB和c-Jun信号传导将通过HIV-1衣壳中的工程修饰在DC中被激活; DC核酸酶TREX 1和RNASEH 2的破坏将允许HIV-1逆转录物积累至激活1型IFN的水平; PRR如cGAS将由HIV-1本身递送，以放大先天免疫信号传导。将鉴定这些使DC成熟以最佳地引发抗HIV-1特异性CD 4+和CD 8 + T细胞应答的干预的组合，并且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，则为开发有效的抗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.