A vaccine for genital herpes that achieves sterilizing immunity

摘要 预防生殖器疱疹的疫苗是一个高度优先的公共卫生事项。表现良好的疱疹疫苗 在啮齿动物中没有保护人类;因此，需要新的方法。我们建议如下： 1)为动物模型中的疫苗效力设定了比以前更高的标准。A的“黄金标准” 疱疹疫苗是消毒免疫，定义为没有生殖器病变，没有亚临床的证据 通过感染后第2天阴性阴道滴度测量的感染，无复发性阴道炎发作 背根神经节内有HSV-2 DNA脱落，无HSV-2 DNA脱落。先前的疱疹候选疫苗 预防死亡和减少生殖器病变，但没有一个接近实现绝育免疫， 预防亚临床感染。我们的目标是使95%以上的动物获得绝育免疫。 2)制定策略，防止病毒逃避疫苗诱导的免疫力。抗体与 保护我们绝大多数有效的人类疫苗。HSV编码糖蛋白C（gC）和E（gE） 免疫逃避分子抑制抗体和补体。我们的疫苗战略建立在 该抗体可抑制gD提供的免疫力，并阻断病毒逃避抗体和补体攻击的能力。 3)修改抗原递送方法。我们使用核苷修饰的mRNA，而不是亚基蛋白， 免疫原我们报告了使用含有修饰mRNA的三价疫苗在小鼠中的初步结果 编码糖蛋白C、D和E（gC 2/gD 2/gE 2），以脂质纳米颗粒形式给药。经修饰的mRNA 用1-甲基假尿苷残基取代尿苷核苷。我们在63/64中实现了灭菌免疫 (98%）的小鼠，而用亚单位抗原免疫的小鼠为14/20（70%）。我们将把这个激动人心的 结果包括在未感染和HSV-1阳性豚鼠中进行的研究，作为疫苗有效性的更严格试验， 评估雄性和雌性动物，并确定针对生殖器HSV-1的交叉保护。 4)定义实现灭菌免疫所需的免疫相关性。我们将评估血清ELISA滴度， 中和滴度，阻断细胞间扩散的抗体，阻断gC和gE免疫逃避的抗体， 抗体依赖性细胞毒性滴度，粘膜ELISA和中和抗体作为免疫 保护的相关性。这些研究将有助于为未来的人体试验建立免疫原性靶点。 5)确定mRNA免疫是否产生针对关键表位的抗体。关键表位 包括中和病毒gC和gD上的那些，抑制补体和抗体的gC和gE上的那些，以及gD和 参与细胞间扩散的gE。我们将使用一种新的高通量生物传感器平台，以确定是否 免疫产生针对这些关键表位的抗体。测量表位特异性抗体应答 将确定免疫原性的差距，并指导我们对这些表位进行修饰，以增强疫苗的保护作用。 这四个实验室联合起来的专业知识，以开发一种生殖器疱疹疫苗，实现消毒 在动物中以及随后在人类中的免疫力。

Abstract A vaccine for prevention of genital herpes is a high public health priority. Herpes vaccines that performed well in rodents have not protected humans; therefore, novel approaches are needed. We propose the following: 1) Set a much higher bar for vaccine efficacy in animal models than used previously. The “gold standard” for a herpes vaccine is sterilizing immunity, defined as no genital lesions and no evidence of subclinical infection as measured by negative day 2 vaginal titers post-infection, no recurrent episodes of vaginal shedding of HSV-2 DNA and no HSV-2 DNA in dorsal root ganglia. Prior herpes candidate vaccines have prevented death and reduced genital lesions, but none has come close to achieving sterilizing immunity by preventing subclinical infection. We have set sterilizing immunity in >95% of animals as our goal. 2) Devise strategies to prevent the virus from evading vaccine-induced immunity. Antibodies correlate with protection for the vast majority of our effective human vaccines. HSV encodes glycoproteins C (gC) and E (gE) that are immune evasion molecules that inhibit antibody and complement. Our vaccine strategy builds upon the immunity provided by gD and blocks the ability of the virus to evade antibody and complement attack. 3) Modify antigen delivery methods. We use nucleoside-modified mRNA, rather than subunit proteins as immunogens. We report preliminary results in mice using a trivalent vaccine that contains modified mRNA encoding glycoproteins C, D and E (gC2/gD2/gE2) administered in lipid nanoparticles. The modified mRNA replaces uridine nucleosides with 1-methylpseudouridine residues. We achieve sterilizing immunity in 63/64 (98%) mice compared with 14/20 (70%) immunized with subunit antigens. We will extend this exciting result to include studies in naïve and HSV-1 positive guinea pigs as a more stringent test of vaccine efficacy, evaluate male and female animals, and determine cross-protection against genital HSV-1. 4) Define the immune correlates required to achieve sterilizing immunity. We will assess serum ELISA titers, neutralizing titers, antibodies that block cell-to-cell spread, antibodies that block gC and gE immune evasion, antibody-dependent cellular cytotoxicity titers, and mucosal ELISA and neutralizing antibodies as immune correlates of protection. These studies will help establish immunogenicity targets for future human trials. 5) Determine whether mRNA immunization produces antibodies to crucial epitopes. The crucial epitopes include those on gC and gD that neutralize virus, gC and gE that inhibit complement and antibody, and gD and gE involved in cell-to-cell spread. We will use a novel high throughput biosensor platform to determine whether immunization produces antibodies to these crucial epitopes. Measuring epitope specific antibody responses will identify gaps in immunogenicity and guide us on those epitopes to modify to enhance vaccine protection. The four labs have the combined expertise to develop a genital herpes vaccine that achieves sterilizing immunity in animals and subsequently in humans.