DESIGN OF IMMUNOGENS FOR ANTIHIV T HELPER CELLS AND CTL

这个项目的总体目标是开发一种实用的HIV免疫原，它将产生持久的和广泛反应的抗HIV T辅助细胞(Th)和MHC限制性CD8+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感染活的HIV可以产生识别特定免疫优势表位的CD8+CTL。一个需要检验的主要假设是，用HIV Th-CTL多肽或在改良的安卡拉(MVA)痘苗中表达的HIV Th-CTL表位的线性阵列免疫，将诱导对这些表位的免疫显性CTL反应，否则这些表位在整个蛋白质背景下是非显性的。具体目的是：1)研究由Th和CTL决定簇组成的多价Th-CTL HIV多肽免疫原在小鼠、恒河猴和人身上的免疫原性；2)确定表达Aim 1中线性Th-CTL多肽基因的MVA的免疫原性，并比较每个Th和CTL表位在MVA中表达时与Th-CTL合成肽的混合物的免疫原性；3)为了诱导持久的保护性细胞抗HIV免疫反应，我们将通过佐剂制剂、T细胞和树突状细胞的趋化因子、树突状细胞CD40的配体和血管生成因子来增加HIV免疫原免疫后存在的效应CTL(ECTL)和记忆(前体)CTL(PCTL)的池规模，以增加免疫细胞在免疫部位的募集。特定目标4将在第一阶段的人体临床试验中测试最优的MVA/多肽免疫原初始/BOAST免疫方案以及最佳的免疫配方和路线。在目标5中，David Montefiori将对第一个和第二个项目中使用含有env的疫苗免疫的动物的血清进行中和分析。这项工作应该为理解如何在人类中诱导有益的抗HIV T辅助细胞和CTL免疫反应提供关键信息。

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.