Blocking granzyme-mediated immune suppression to enhance HIV vaccine efficacy

总结 免疫接种是人类历史上最成功的公共卫生干预措施之一， 每年超过两百万人死亡。疫苗的成功取决于抗体的可变组合， 可以中和入侵的病原体和杀死受感染目标的病毒特异性T细胞。然而，归纳 中和抗体和抗病毒T细胞，它们具有足够的功能和广泛的靶向， 像HIV这样高度可变病原体在人类和动物模型中被证明是非常困难的。因此，在本发明中， 目前还没有有效的疫苗来预防每天发生的近5,000例新的艾滋病毒感染。 疫苗成功的这一缺点可能是由于内在的免疫调节机制限制了疫苗的免疫效果。 艾滋病毒特异性免疫反应的数量和质量。开发翻译手段来克服这些问题 免疫学障碍为下一代预防艾滋病毒疫苗的发展带来了巨大希望 感染和改善全球健康。 我们的研究集中在自然杀伤（NK）细胞的显着能力，以抑制幅度和 免疫后引发的抗病毒T和B细胞应答的质量。NK细胞会削弱 通过抑制滤泡辅助性T细胞反应和限制亲和力的保护性中和抗体反应 抗体在生殖中心内成熟。这种NK细胞免疫抑制也限制了NK细胞的数量， 抗病毒记忆T细胞应答的质量。NK细胞通过穿孔素依赖性免疫抑制作用实现这种抑制作用。 杀伤活化的T细胞，尽管用于识别靶T细胞和穿孔素递送的特异性受体 参与触发细胞死亡的颗粒酶仍然不完全确定。而抑制穿孔素则可以 减少NK细胞介导的免疫抑制，这种广泛的方法可能会暂时破坏免疫力 针对病原体和肿瘤，因此提出了一种更精细的靶向颗粒酶的方法。 因此，本提案的目标是推进一种创新的高风险、高影响的方法，以促进艾滋病毒 通过选择性抑制参与NK细胞免疫抑制活性的颗粒酶来提高疫苗效力。 在小鼠中的初步实验将使用小分子抑制剂和CRISPR来定义靶向特定靶点的效用。 颗粒酶限制NK细胞杀伤T细胞和抑制疫苗引起的适应性免疫。选择抑制剂 将在恒河猴中得到验证。基于定量定义的通过/不通过标准，确定成功 的颗粒酶靶向，以提高疫苗的效力，我们将继续评估这种方法在疫苗- 介导的预防非人灵长类动物中的SIV感染。这些实验也将开启有影响力的 研究NK细胞的免疫抑制亚群的分子特征的途径， 靶向T细胞亚群。因此，拟议的工作将促进随后的发展， 部署创新战略，提高艾滋病毒疫苗的效力。

SUMMARY Immunization represents one of the most successful public health interventions in human history, preventing more than 2 million deaths each year. Vaccine success depends on a variable combination of antibodies that can neutralize the invading pathogen and virus-specific T cells that kill infected targets. However, the induction of neutralizing antibodies and antiviral T cells that are sufficiently functional and broadly targeted to thwart a highly mutable pathogen like HIV has proven exceptionally difficult in both humans and animal models. Thus, there is currently no efficacious vaccine to prevent the nearly 5,000 new infections with HIV that occur each day. This shortcoming in vaccine success is likely due to intrinsic immune regulatory mechanisms that limit the quantity and quality of HIV-specific immune responses. Development of translational means to overcome these immunological roadblocks holds great promise for advancement of next-generation vaccines to prevent HIV infection and improve global health. Our research focuses on the remarkable capacity of natural killer (NK) cells to suppress the magnitude and quality of antiviral T and B cell responses triggered after immunization. NK cells impair the generation of protective neutralizing antibody responses by inhibiting follicular helper T cell responses and restricting affinity maturation of antibodies within germinal centers. This NK-cell immunosuppression also limits the quantity and quality of antiviral memory T cell responses. NK cells achieve this suppressive effect via perforin-dependent killing of activated T cells, although the specific receptors used to recognize target T cells and perforin-delivered granzymes involved in triggering cell death remain incompletely defined. Whereas inhibition of perforin could curtail NK cell-mediated immune suppression, this broad of an approach could temporarily undermine immunity against pathogens and tumors, and thus a more refined approach targeting granzymes is proposed. Therefore, the goal of this proposal is to advance an innovative high risk, high impact approach to foster HIV vaccine efficacy through selective inhibition of granzymes involved in the immunosuppressive activity of NK cells. Initial experiments in mice will use small molecule inhibitors and CRISPR to define the utility of targeting a specific granzyme to limit NK-cell killing of T cells and suppression of vaccine-elicited adaptive immunity. Select inhibitors will be validated in Rhesus macaques. Based on quantitatively defined go/no-go criteria establishing the success of granzyme targeting to enhance vaccine efficacy, we will proceed to evaluation of this approach in vaccine- mediated prevention of SIV infection in non-human primates. These experiments will also open impactful avenues of investigation into the molecular features of both the immunosuppressive subset of NK cells and targeted subpopulation of T cells. Thus, the proposed work will facilitate subsequent development and deployment of innovative strategies to enhance HIV vaccine efficacy.