DESIGN OF IMMUNOGENS FOR ANTIHIV T HELPER CELLS AND CTL

该项目的总体目标是开发一种实用的HIV免疫原，该免疫原将产生持久和广泛反应性的抗HIV辅助性T细胞（Th）和MHC限制性CD 8+细胞毒性T淋巴细胞（CTL）反应。最近的研究表明，用表达完整HIV蛋白的活载体免疫或用活HIV感染产生识别选择的免疫显性表位的CD 8 + CTL。待检验的一个主要假设是，用HIV Th-CTL肽或在修饰的安卡拉牛痘（MVA）中表达的HIV Th-CTL表位的线性阵列免疫将诱导对那些表位的免疫显性CTL应答，否则这些表位在整个蛋白质的背景下是非显性的。具体目标是：1）研究由Th和CTL决定簇组成的多价Th-CTL HIV肽免疫原，并在小鼠、恒河猴和人中进行免疫原性试验; 2）测定表达Aim 1中的Th-CTL肽线性阵列基因的MVA的免疫原性，并比较当在MVA中表达与在Th-CTL合成肽的混合物中表达时，Th和CTL表位中的每一个的免疫原性; 3）为了诱导持久的保护性细胞抗HIV免疫应答，我们将通过加入佐剂制剂、T细胞和树突细胞的趋化因子、树突细胞CD 40的配体和血管生成因子来增加用HIV免疫原免疫后存在的效应CTL（eCTL）和记忆（前体）CTL（pCTL）的库大小，以增加免疫细胞募集到免疫部位。具体目标4将在1期人类临床试验中测试最佳MVA/肽免疫原初免/扩增免疫方案以及最佳制剂和免疫途径。在目标5中，大卫蒙特菲奥里将对第一个和第二个项目的含env疫苗免疫动物的血清进行中和试验。这项工作将为了解如何在人体内诱导有益的抗HIV辅助性T细胞和CTL免疫应答提供关键信息。

The overall goal of this project is to develop a practical HIV immunogen that will give rise to long-lasting and broadly reactive anti-HIV T helper cell (Th) and MHC-restricted CD8+ cytotoxic T lymphocyte (CTL) responses. Recent studies have demonstrated that immunization with live vectors expressing whole HIV proteins or infection with live HIV gives rise to CD8+ CTL that recognize select immunodominant epitopes. A major hypothesis to be tested is that immunization with either HIV Th-CTL peptides or linear arrays of HIV Th-CTL epitopes expressed in modified vaccinia ankara (MVA) vaccinia will induce immunodominant CTL responses to those epitopes that are otherwise non-dominant in the context of whole proteins. Specific aims are: 1) to study multivalent Th-CTL HIV peptide immunogens comprised of Th and CTL determinants with tests for immunogenicity in mice, rhesus monkeys and humans; 2) to determine the immunogenicity of MVA that express the genes of the linear arrays of Th- CTL peptides in Aim 1, and compare the immunogenicity of each of the Th and CTL epitopes when expressed in MVA versus mixtures of Th-CTL synthetic peptides; 3) to induce durable protective cellular anti-HIV immune responses, we will augment the pool size of effector CTL (eCTL) and memory (precursor) CTL (pCTL) present after immunization with HIV immunogens by addition to adjuvant formulations, chemokines for T and dendritic cells, ligands for dendritic cell CD40, and angiogenic factors to augment immune cell recruitment into the immunization site. Specific aim 4 will test the optimal MVA/peptide immunogen prime/boast immunization protocol and optimal formulation and route of immunization in a Phase 1 human clinical trial. In aim 5, David Montefiori will perform neutralization assays on sera from animals immunized with env- containing vaccines from the first and second projects. This work should provide key information for understanding how to induce salutary anti- HIV T helper and CTL immune responses in humans.