DEVELOPMENT OF AN OPTIMAL LIVE ATTENUATED SIV VACCINE

SIV的减毒单核细胞克隆(SIV/17E-C1)具有 它们是减毒活疫苗所特有的。感染了 SIV/17E-C1诱导早期强效型中和抗体 在感染后的头7个月内扩大到 包括对异源初级分离物SIV/DeltaB670活性。 保护性免疫反应的诱导与开关是一致的 从类型特异性中和抗体到组特异性中和抗体，并且至少 在一定程度上，似乎是由抗体介导的，因为受保护猴子的血清 被动保护4个收件人中的2个。被nef删除的变体 亲单核细胞的克隆，但不亲淋巴细胞的亲本 SIVmac239deltanef也诱导了可检测到的I类限制性CTL 感染后前6个月。这些独特的性质很可能是由于 到独特的gp120构象，这是由序列强加的，使它能够 在巨噬细胞中复制，和/或选择性地呈现给免疫 系统被感染的巨噬细胞感染。我们建议进一步刻画 SIV/17E-C1感染诱导的保护性反应及其利用 这些信息来设计一种亚单位疫苗，可以诱导 用减毒病毒观察到的保护性反应。保护 用SIV/e-c1无细胞病毒静脉攻击观察 被感染的猴子将被扩展到保护免受感染的细胞， 静脉给药和肠粘膜表面给药。这个 抗体在被动保护中的作用将通过被动来确认 纯化的免疫球蛋白的转移。与天然抗体结合的抗体与 变性的gp120将进行亲和纯化，体外鉴定和 类似地进行分析，以确定保护性反应的特异性。 被动转移研究也将用单抗进行。 从感染SIV/17E-C1的猴子中提取抗体以识别 保护所需的特定表位(S)。的贡献 细胞免疫将通过确定类的动力学来确定。 我限制了在感染的猴子中诱导CTL，并将这些 对保护的反应。纯化的重组gp120的免疫效果 将对由SIV/17E-C1序列组成的疫苗进行评估，以确定 这些序列本身是否独特地诱导保护性免疫。这个 由SIV/17E序列组成的DNA疫苗单独或联合免疫的能力 与细胞因子表达载体结合，诱导保护性 反应将通过直接注射DNA和 颗粒输送系统由AGRACCEUS公司开发。最理想的HIV疫苗 策略是一种对SIV(疾病)和HIV都有效的策略 (感染)模型系统。因此，SIV/HIV重组的能力 作为减毒活疫苗的病毒将被确定延长 SIV对HIV糖蛋白的观察结果。一种模型 评估有效的SIV亚单位疫苗以及异源疫苗(内部 分支)保护，将使用Shiv构造来建立。

An attenuated monocyte-tropic clone of SIV (SIV/17E-C1) has properties which are unique to a live attenuated SIV vaccine. Infection with SIV/17E-C1 induces an early vigorous type-specific neutralizing antibody response which broadens during the first 7 months postinfection to include activity against SIV/DeltaB670, a heterologous primary isolate. The induction of protective immune responses coincides with the switch from type-specific to group-specific neutralizing antibody, and, at least in part, appears mediated by antibody since sera from protected monkeys passively protected 2 of 4 recipients. A nef-deleted variant of this monocyte-tropic clone, but not the lymphocyte-tropic parent SIVmac239deltanef, also induced detectable class I restricted CTL during the first 6 months postinfection. These unique properties are likely due to a unique gp120 conformation imposed by sequences which enable it to replicate in macrophages, and/or selective presentation to the immune system by the infected macrophage. We propose to further characterize the protective responses induced by SIV/17E-C1 infection, and to utilize this information to design a subunit vaccine that can induce the protective responses observed with the attenuated virus. The protection observed by intravenous challenge with cell-free virus of SIV/e-C1- infected monkeys will be extended to protection against infected cells, delivered both intravenously and at the intestinal mucosal surface. The role of antibody in passive protection will be confirmed by passive transfer of purified immunoglobulin. Antibodies binding to native versus denatured gp120 will be affinity purified, characterized in vitro and similarly analyzed to define the specificity of protective responses. Passive transfer studies will also be performed with monoclonal antibodies derived from SIV/17E-C1-infected monkeys to identify the specific epitope(s) required for protection. The contribution of cellular immunity will be determined by determining the kinetics of class I restricted CTL induction in infected monkeys, and correlating these responses to protection. The efficacy of a purified recombinant gp120 vaccine comprised of SIV/17E-C1 sequences will be evaluated to determine whether these sequences per se uniquely induce protective immunity. The ability of DNA vaccines comprised of SIV/17E sequences, alone or in combination with cytokine expression vectors, to elicit protective responses will be assessed using both direct injection of DNA and the particle delivery system developed by Agracetus. The optimal HIV vaccine strategy is one which is efficacious in both SIV (disease) and HIV (infection) model systems. Thus, the ability of SIV/HIV recombinant viruses to serve as live attenuated vaccines will be determined to extend the observations gained from SIV to HIV glycoproteins. A model for assessing effective SIV subunit vaccines, as well as heterologous (inter- clade) protection, will be established using SHIV constructs.