Identification And Characterization Of Immunogenic Epito

免疫原性表位的鉴定和表征

• 批准号: 6669708
• 负责人: Anthony S. Fauci
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6669708
• 关键词: HIV envelope protein; HIV infections; Macaca; Macaca mulatta; antibody specificity; antigen antibody reaction; biomimetics; biotechnology; enzyme linked immunosorbent assay; epitope mapping; human immunodeficiency virus 1; human tissue; immunoregulation; laboratory mouse; nucleic acid sequence; peptide library; polymerase chain reaction; vaccine development

Efforts to develop a protective HIV-1 vaccine have been hindered by difficulties in identifying epitopes capable of inducing broad neutralizing antibody responses. In addition, the high mutation rate occurring in the gene encoding HIV-1 envelope proteins and the complex structure of gp120 as an oligomer associated with gp41 result in a high degree of antigenic polymorphism. Finally, a vaccine formulation must incorporate the subtype prevalence in different geographic regions as well as the insurgence of new HIV isolates. Therefore, we screened Random Peptide Libraries using sera from HIV-infected subjects in order to identify antigenic and immunogenic mimics of HIV-1 epitopes. After extensive counter-screening with HIV-negative sera, we isolated peptides specifically recognized by antibodies from HIV- 1 infected individuals. These peptides behaved as antigenic mimics of linear or conformational HIV-1 or SHIV epitopes generated in vivo in the course of natural infection. The selected epitopes were immunogenic in mice, eliciting HIV-specific antibodies that effectively neutralized HIV-1 isolates. Although the HIV-1 mimotopes were isolated by using clade B sera, they reacted with antibodies from subjects infected with different HIV-1 clades, including clade A, C, D, E, and F. These data suggest that the epitopes that we identified function as antigenic mimics of HIV-1 epitopes shared by multiple HIV-1 strains and subtypes from distant geographic regions. Consistent with these findings, sera of monkeys infected with SHIVs carrying envelopes from different primary isolates, such as DH12, 89.6 and 89.6P, also recognized the pool of HIV-specific epitopes. When injected in Rhesus macaques with QS21 adjuvant, a pool of five epitopes induced an antibody response specific for each of the single epitope and this response cross-reacted with HIV-1 envelope proteins. Recently, hese animals have been challenged intravenously with the highly pathogenic strain SHIV89.6PD to evaluate the level of protection induced by the selected epitopes. Thus, this novel approach to generate effective antibody responses against HIV-1 may contribute to the development of an effective vaccine.

由于难以识别能够诱导广泛中和抗体反应的表位，开发保护性HIV-1疫苗的努力受到了阻碍。此外，HIV-1包膜蛋白编码基因的高突变率以及gp120作为与gp41相关的寡聚体的复杂结构导致了高度的抗原多态。最后，疫苗配方必须包含不同地理区域的亚型流行率以及新的艾滋病毒分离株的暴动。因此，我们利用HIV感染者的血清筛选随机肽库，以鉴定HIV-1表位的抗原性和免疫原性模拟物。在用HIV阴性血清进行广泛的反筛选后，我们从HIV-1感染者中分离出了抗体特异性识别的多肽。这些多肽表现为自然感染过程中体内产生的线性或构象HIV-1或SIV表位的抗原性模拟。选定的表位在小鼠中具有免疫原性，产生的HIV特异性抗体可以有效地中和HIV-1分离株。虽然HIV-1模拟表位是用B分支血清分离的，但它们与来自不同HIV-1分支感染者的抗体发生反应，包括A、C、D、E和F分支。这些数据表明，我们鉴定的表位是对来自遥远地理区域的多种HIV-1毒株和亚型共享的HIV-1表位的抗原模拟。与这些发现一致的是，携带不同初级分离株(如DH12、89.6和89.6P)包膜的SHIV感染猴子的血清也识别HIV特异性表位池。当用QS21佐剂注射恒河猴时，五个表位池诱导了针对每个表位的抗体反应，这种反应与HIV-1包膜蛋白发生交叉反应。最近，这些动物被静脉注射高致病性菌株SHIV89.6PD来评估所选表位诱导的保护水平。因此，这种产生针对HIV-1的有效抗体反应的新方法可能有助于开发有效的疫苗。