Identification And Characterization Of Immunogenic Epito

开发保护性HIV-1疫苗的努力受到鉴定能够诱导广泛中和抗体应答的表位的困难的阻碍。此外，编码HIV-1包膜蛋白的基因中发生的高突变率和作为与gp 41相关的寡聚体的gp 120的复杂结构导致高度的抗原多态性。最后，疫苗配方必须考虑不同地理区域的亚型流行率以及新的HIV分离株的出现。因此，我们使用来自HIV感染受试者的血清筛选随机肽文库，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感染者中分离出被抗体特异性识别的肽。这些肽表现为在自然感染过程中体内产生的线性或构象HIV-1或SHIV表位的抗原模拟物。所选择的表位在小鼠中具有免疫原性，引发HIV特异性抗体，有效中和HIV-1分离株。尽管HIV-1模拟表位是使用进化枝B血清分离的，但它们与来自感染不同HIV-1进化枝（包括进化枝A、C、D、E和F）的受试者的抗体反应。这些数据表明，我们鉴定的表位作为来自遥远地理区域的多个HIV-1毒株和亚型共享的HIV-1表位的抗原模拟物发挥作用。与这些发现一致，感染携带来自不同原代分离株（如DH 12、89.6和89.6P）包膜的SHIV的猴血清也识别HIV特异性表位库。当用QS 21佐剂注射恒河猴时，5个表位的库诱导对每个单个表位特异的抗体应答，并且该应答与HIV-1包膜蛋白交叉反应。最近，这些动物已经被高致病性毒株SHIV 89.6PD静脉内攻击，以评估所选择的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。

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.