CTL RECOGNITION OF DOMINANT AND CRYPTIC HIV-1 EPITOPES

在HIV感染中，病毒特异性CTL可能在 主场防守。首席研究员对CTL的初步分析 Gp160基因相对保守区的识别 种群的多样性表明MHC限制元件在用于 优先使用某些MHC等位基因和 受最普遍的MHC等位基因限制的表位显著缺失 这些基因在76%的研究人群中表达。这样做的一个目的是 建议将这些研究扩展到包括特定于隔离的环境 表位和其他HIV蛋白，看看是否有类似的偏见 在其识别中使用的限制元素。在这些研究中， 从保存的人类白细胞抗原分型样本中获得多肽特异性T细胞系 将使用血清阳性的受试者来确定限制因素 对于免疫优势的env，则为Gag RT表位。最新技术进步 这表明，通过实验操作，可能会使物种多样化 免疫应答或产生比现在更有效的免疫应答 见于自然感染。这项提议涉及的第二个问题是 是否有可能对特定表位产生CTL反应 即使它们在自然感染中不是免疫优势的。不同 使用高纯度的多肽脉冲树突状细胞等策略， 修饰APC以增加外源添加的多肽的结合 而在APC中以Miniges形式过度表达的多肽将是 试图引起对神秘和次优势表位的反应。肽类 选择与流行的MHC高亲和力结合以及所看到的 作为免疫优势在一些HIV血清阳性的人中将被用于 这项研究。然而，由于CTL的体内有效性最终将 依赖于它们杀死受感染的CD4+细胞的能力，CTL针对 将对免疫优势表位或实验诱导的表位进行检测 杀灭HIV感染的CD4目标的有效性。在这些研究中，CD4+ 统一表达病毒的细胞将使用 含新霉素的HIV、R7、neo感染性分子克隆 阻力标记物。将使用G418中选择的病毒感染细胞 作为杀戮测试的靶子。这些研究可能会提供 对外系人类免疫缺陷病毒CTL反应的本质的洞察 并可能对疫苗设计和免疫治疗产生影响。

In HIV-infection, viral specific CTL are likely to play a crucial role in host defense. The principal investigator's preliminary analysis of CTL recognition of relatively conserved regions of gp160 in a genetically diverse population suggests a bias in MHC restriction elements used for the response, with a preferential usage of certain MHC alleles and a striking absence of epitopes restricted by the most prevalent MHC alleles which are expressed by 76% of the study population. One aim of this proposal is to extend these studies to include isolate-specific env epitopes and other HIV proteins to see if there is a similar bias in restriction elements used in their recognition. For these studies, peptide-specific T cell lines generated from stored samples of HLA typed seropositive subjects will be used to determine the restricting elements for immunodominant env, gag RT epitopes. Recent technical advances suggest that by experimental manipulation, it may be possible to diversify the immune response or generate a more effective immune response than is seen in natural infection. The second question this proposal addresses is whether it is possible to generate CTL response to particular epitopes even though they are not immunodominant in natural infection. Different strategies like using highly purified peptide-pulsed dendritic cells, modifying the APC to increase the binding of exogenously added peptides and over expression of peptides in APC in the form of minigenes will be tried to elicit responses to cryptic and subdominant epitopes. Peptides selected for high affinity binding to prevalent MHC as well as those seen as immunodominant in some HIV seropositive individuals will be used for the study. However, since in vivo effectiveness of CTL will ultimately depend on their ability to kill infected CD4+ cells, CTL directed against immunodominant epitopes or those induced experimentally will be tested for effectiveness in killing HIV infected CD4 targets. For these studies CD4+ cells uniformly expressing the virus will be generated using the infectious molecular clone of HIV, R7, neo containing a neomycin resistance marker. The virus infected cells selected in G418 will be used as targets in killing assays. These studies are likely to provide insights into the nature of the CTL response to HIV in an outbred population and may have implications for vaccine design and immunotherapy.