HSV-2 immune evasion as a virulence factor

HSV-2 免疫逃避作为毒力因子

• 批准号: 9212090
• 负责人: Harvey Michael Friedman
• 金额: $ 40万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-15 至 2019-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9212090
• 关键词: Animal Model; Animals; Antibodies; Antibody titer measurement; Antigens; Binding; Blocking Antibodies; Cavia; Childbirth; Complement; Complement 3b; Complement Activation; Disease; Dose; Effectiveness; Endpoint Determination; Fc domain; Generations; Genital system; Glycoproteins; HIV; HIV Infections; HIV-1; HSV glycoprotein C; Health Benefit; Herpes Simplex Virus Vaccines; Herpesviridae Infections; Herpesvirus 1; Human; Human Herpesvirus 2; Immune; Immune Evasion; Immune response; Immunity; Immunization; Immunize; Immunoglobulin G; Individual; Infant; Infection; Knock-out; Lead; Lesion; Life; Mediating; Modeling; Mus; Passive Transfer of Immunity; Pathogenesis; Predictive Value; Public Health; Recurrence; Risk; Role; Severities; Simplexvirus; Spinal Ganglia; Subunit Vaccines; T cell response; T-Lymphocyte; Testing; Tissues; Ulcer; Vaccine Antigen; Vaccines; Vagina; Viral Antigens; Virulence; Virulence Factors; Virulent; Virus; Virus Replication; Work; acquired immunity; antibody-dependent cell cytotoxicity; base; emotional distress; experimental study; genital herpes; glycoprotein D-herpes simplex virus type 2; human subject; improved; inhibiting antibody; latent infection; mortality; mutant; neutralizing antibody; novel strategies; prevent; protein expression; public health relevance; seroconversion; tool; transmission process; vaccine development; vaccine efficacy; virus culture

DESCRIPTION (provided by applicant): Herpes simplex virus type 2 (HSV-2) infects a half-billion individuals worldwide, which has important public health implications since HSV-2 genital ulcer disease increases the risk of acquiring and transmitting HIV by 3-fold. Our work focuses on immune evasion strategies of HSV-2 glycoproteins C (gC2) and E (gE2). HSV-2 gC2 binds complement component C3b to inhibit complement activation. HSV-2 gE2 blocks Fc- mediated activities by binding the Fc domain of an IgG antibody molecule that is bound by its F(ab')2 domain to HSV antigen, which inhibits complement activation and antibody-dependent cellular cytotoxicity (ADCC). In Aim 1 we will evaluate the hypothesis that gC2 and gE2 immune evasion greatly reduce the effectiveness of an HSV-2 glycoprotein D (gD2) vaccine in humans by inhibiting antibody and complement, and that gC2 and gE2 immune evasion contribute to recurrent genital disease after naturally acquired infection. We will test our hypothesis by evaluating sera from subjects immunized with the GSK gD2 subunit vaccine to determine whether gC2 and gE2 immune evasion inhibit antibody and complement neutralization and ADCC, and by assessing sera obtained from subjects with multiple recurrences of genital HSV-2 or with no recurrences to evaluate the contribution of gC2 and gE2 immune evasion to recurrent genital ulcer disease. In Aim 2 we will assess the hypothesis that HSV-2 gC2 and gE2 mutant strains defective in immune evasion will be log10 orders of magnitude less virulent than wild-type or recue virus in mouse and guinea pig vaginal infection models. We will test our hypothesis by constructing single gC2 and gE2 mutant strains and a double gC2/gE2 mutant strain that are defective in immune evasion but intact for replication, protein expression and other functions ascribed to them. We will determine the magnitude of the impact of immune evasion in mice and guinea pigs and define mechanisms using complement and NK deficient animals. In Aim 3 we will evaluate the hypothesis that a gC2/gD2/gE2 vaccine totally protects against genital ulcer disease and markedly reduces or totally prevents latency. We will define the optimum dose of gC2 and gE2 antigen that induce high titers of antibodies that block immune evasion and of gD2 antigen that induces high titers of neutralizing antibodies. We will then evaluate whether the trivalent vaccine provides better protection against genital disease and latent infection than any single antigen or double antigen combination. To improve the translatability of animal models to human studies, we will modify endpoint determinations in animal models to match human trials, including confirming disease scores by seroconversion, PCR and culture. We will determine if local virus replication in vaginal tissues is sufficient to induce seroconversion in immunized animals that have no genital disease or latent infection. Detecting seroconversion under these conditions would be informative since it is may not serve as a useful marker for latency in human trials. These studies take a novel approach to vaccine development and may lead to a new generation of vaccines.

描述（由申请人提供）：2 型单纯疱疹病毒 (HSV-2) 感染了全世界 5 亿人，这具有重要的公共卫生影响，因为 HSV-2 生殖器溃疡病会使感染和传播 HIV 的风险增加 3 倍。我们的工作重点是 HSV-2 糖蛋白 C (gC2) 和 E (gE2) 的免疫逃避策略。 HSV-2 gC2 结合补体成分 C3b 以抑制补体激活。 HSV-2 gE2 通过结合 IgG 抗体分子的 Fc 结构域来阻断 Fc 介导的活性，该抗体分子通过其 F(ab')2 结构域与 HSV 抗原结合，从而抑制补体激活和抗体依赖性细胞毒性 (ADCC)。 在目标 1 中，我们将评估以下假设：gC2 和 gE2 免疫逃避通过抑制抗体和补体，大大降低 HSV-2 糖蛋白 D (gD2) 疫苗在人类中的有效性，并且 gC2 和 gE2 免疫逃避导致自然获得性感染后复发性生殖器疾病。我们将通过评估来自 GSK gD2 亚单位疫苗免疫受试者的血清来检验我们的假设，以确定 gC2 和 gE2 免疫逃避是否抑制抗体和补体中和和 ADCC，并通过评估从生殖器 HSV-2 多次复发或未复发的受试者获得的血清来评估 gC2 和 gE2 免疫逃避对复发性生殖器溃疡病的贡献。在目标 2 中，我们将评估以下假设：在小鼠和豚鼠阴道感染模型中，免疫逃避缺陷的 HSV-2 gC2 和 gE2 突变株的毒性比野生型或恢复型病毒低 log10 个数量级。我们将通过构建单 gC2 和 gE2 突变株以及双 gC2/gE2 突变株来检验我们的假设，这些突变株在免疫逃避方面存在缺陷，但在复制、蛋白质表达和其他功能方面完好无损。我们将确定免疫逃避对小鼠和豚鼠的影响程度，并使用补体和 NK 缺陷动物来定义机制。 在目标 3 中，我们将评估 gC2/gD2/gE2 疫苗完全预防生殖器溃疡病并显着减少或完全防止潜伏期的假设。我们将确定诱导高滴度抗体（阻止免疫逃避）的 gC2 和 gE2 抗原的最佳剂量，以及诱导高滴度中和抗体的 gD2 抗原的最佳剂量。然后，我们将评估三价疫苗是否比任何单抗原或双抗原组合能提供更好的针对生殖器疾病和潜伏感染的保护。为了提高动物模型向人体研究的可转化性，我们将修改动物模型中的终点确定以匹配人体试验，包括通过血清转化、PCR 和培养来确认疾病评分。我们将确定阴道组织中的局部病毒复制是否足以在没有生殖器疾病或潜伏感染的免疫动物中诱导血清转化。在这些条件下检测血清转化将提供丰富的信息，因为它可能无法作为人体试验中潜伏期的有用标记。这些研究采用了一种新的疫苗开发方法，可能会产生新一代疫苗。