CTL RECOGNITION OF DOMINANT AND CRYPTIC HIV-1 EPITOPES

CTL 对显性和隐性 HIV-1 表位的识别

• 批准号: 2887081
• 负责人: Premlata Shankar
• 金额: $ 14.49万
• 依托单位: IMMUNE DISEASE INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-01 至 2001-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2887081
• 关键词: B lymphocyte; HIV envelope protein gp160; MHC class I antigen; antigen presentation; cytotoxic T lymphocyte; dendritic cells; helper T lymphocyte; human immunodeficiency virus 1; human tissue; immunoregulation; microorganism immunology; polymerase chain reaction; tissue /cell culture; vaccinia virus; virus antigen; virus replication

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.

在HIV感染中，病毒特异性CTL可能在HIV感染中起关键作用。 宿主防御 主要研究者对CTL的初步分析 在一个基因组中识别gp160的相对保守区域， 不同的人群表明，在MHC限制性元件用于 这种反应，具有某些MHC等位基因的优先使用， 显著缺乏受最普遍的MHC等位基因限制的表位 这在76%的研究人群中表现出来。 这样做的目的之一 建议将这些研究扩展到包括分离物特异性env 表位和其他HIV蛋白质，看看是否有类似的偏见， 在其识别中使用的限制元素。 对于这些研究， 肽特异性T细胞系产生自HLA分型的储存样品， 血清阳性受试者将用于确定限制因素 免疫显性env，gag RT表位。 最近的技术进展 这表明，通过实验操作， 免疫反应或产生比 在自然感染中可见。 这一建议所涉及的第二个问题是 是否可能产生针对特定表位的CTL应答 尽管它们在自然感染中不是免疫显性的。 不同 策略如使用高度纯化的肽脉冲树突细胞， 修饰APC以增加外源添加的肽的结合 并且肽在APC中以小基因的形式过度表达将是 试图引起对隐蔽和次显性表位的反应。 肽 选择高亲和力结合流行的MHC，以及那些看到 由于在一些HIV血清阳性个体中免疫显性， 书房 然而，由于CTL的体内有效性将最终 依赖于它们杀死受感染的CD4+细胞的能力， 免疫显性表位或实验诱导的表位将被测试， 有效杀死HIV感染的CD4靶点。 对于这些研究，CD4+ 将使用该方法产生均匀表达病毒的细胞。 含新霉素HIV，R7，neo感染性分子克隆 抗性标记 将使用在G418中选择的病毒感染细胞 作为杀伤测定中的靶。 这些研究可能会提供 深入了解远系繁殖的人对HIV的CTL反应的性质， 这可能对疫苗设计和免疫治疗有影响。