Blocking immune evasion as a novel immunotherapy for recurrent HSV-2 infection

描述(申请人提供)：单纯疱疹病毒2型(HSV-2)是生殖器溃疡的主要原因，感染全球5亿人。生殖器疱疹使人情绪痛苦，对在分娩过程中感染的新生儿构成生命威胁，是感染和传播艾滋病毒的主要危险因素。每日抑制性抗病毒疗法是目前唯一的 可用于复发性生殖器疱疹感染的治疗；然而，这种方法在预防暴发方面只取得了部分成功，在减少艾滋病毒感染方面无效。 我们将评估两种免疫治疗疫苗在控制HSV-2复发感染方面的效果。这些疫苗是我们实验室首创的；一个涉及HSV-2复制能力强的减毒活病毒(gE2-del)，另一个涉及三价亚单位抗原疫苗(GC2/GD2/gE2)。一种具有复制能力的水痘带状疱疹活病毒疫苗目前被用于预防带状疱疹，带状疱疹是一种由密切相关的疱疹病毒引起的反复感染。我们将单独评估活病毒疫苗和亚单位抗原疫苗，并结合预期，活病毒疫苗将刺激CD4+和CD8+T细胞反应，而GC2/GD2/gE2亚单位抗原疫苗将提高体液免疫。包括用于增强中和抗体的HSV-2 gD，用于刺激阻止细胞间传播的抗体的gD2和gE2，以及用于产生防止抗体和补体免疫逃避的抗体的gC2和gE2。三价亚单位抗原作为小鼠初级生殖器疱疹预防性疫苗的令人印象深刻的效果支持了阻止免疫逃避作为反复感染的免疫治疗的概念。 在R21阶段，我们将评估活病毒和三价亚单位抗原疫苗降低豚鼠反复生殖道感染的频率和严重程度的能力。我们会 确定免疫治疗是否减少了允许HIV复制的CD4+T细胞在生殖器组织中的渗透(R33期)。我们将通过测量模拟疫苗或最佳治疗性疫苗(R33阶段)免疫的HSV-2感染豚鼠的先天、抗体和T细胞免疫反应，来评估预防反复生殖器感染的免疫相关性。确定保护的免疫相关性将有助于未来的研究，解决是否可以在感染HSV-2的人类中产生类似的免疫反应。我们将确定GC2/GD2/gE2亚单位抗原治疗性免疫是否选择体内在免疫压力下出现的突变株，方法是使用单基因组扩增(SGA)技术比较在病毒接种物、急性感染期间分离的病毒和治疗性免疫后(R21和R33期)分离的病毒中检测到的突变变体。SGA为病毒库中的微小突变变异提供了一种准确的检测方法，与其他测序方法相比，该方法对检测构象表位的突变更敏感，是一种创新的方法，可以识别其他成功的免疫治疗性疫苗的潜在有害后果。

DESCRIPTION (provided by applicant): Herpes simplex virus type 2 (HSV-2) is the leading cause of genital ulcers and infects a half-billion people worldwide. Genital herpes is emotionally distressing, is life threatening to newborns infected during delivery, and is a major risk factor fr acquiring and transmitting HIV infection. Daily suppressive antiviral therapy is currently the only treatment available for recurrent genital herpes infections; however, this approach is only partially successful in preventing outbreaks and is ineffective in reducing HIV acquisition. We will evaluate the efficacy of two immunotherapeutic vaccines at controlling HSV-2 recurrent infection. The vaccines were pioneered in our lab; one involves a HSV-2 replication competent, attenuated live virus (gE2-del) and the other a trivalent subunit antigen vaccine (gC2/gD2/gE2). A replication competent varicella zoster live virus vaccine is currently used to prevent shingles, which is a recurrent infection caused by a closely related herpes virus. We will evaluate the live virus and subunit antigen vaccines individually and in combination with the expectation that the live virus vaccine will stimulate CD4+ and CD8+ T-cell responses, while the gC2/gD2/gE2 subunit antigen vaccine will improve humoral immunity. HSV-2 gD is included to enhance neutralizing antibodies, gD2 and gE2 to stimulate antibodies that block cell-to-cell spread, and gC2 and gE2 to produce antibodies that prevent immune evasion from antibody and complement. The impressive efficacy of the trivalent subunit antigens as a prophylactic vaccine for primary genital herpes in mice supports the concept of blocking immune evasion as immunotherapy for recurrent infections. In the R21 phase, we will evaluate the live virus and trivalent subunit antigen vaccines for their ability to reduce the frequency and severity of recurrent genital infection in guinea pigs. We will determine whether immunotherapy reduces the infiltration into genital tissues of CD4+ T-cells that are permissive for HIV replication (R33 phase). We will evaluate the immune correlates of protection against recurrent genital infection by measuring innate, antibody and T cell immune responses in HSV-2 infected guinea pigs that are either mock-vaccinated or immunized with the best-performing therapeutic vaccine (R33 phase). Defining the immune correlates of protection will facilitate future studies that address whether comparable immune responses can be generated in HSV-2 infected humans. We will determine whether therapeutic immunization with gC2/gD2/gE2 subunit antigens selects for mutants that emerge under immune pressure in vivo by using single genome amplification (SGA) technology to compare mutant variants detected in the virus inoculum, virus isolated during acute infection and virus isolated after therapeutic immunization (R21 and R33 phases). SGA provides an accurate detection assay for minor mutant variants within a virus pool that is more sensitive for detecting mutations in conformational epitopes that other sequencing methods and is an innovative approach to identify potentially unwanted consequences of an otherwise successful immunotherapeutic vaccine.