Protective Human Monoclonal Antibodies to HIV1

描述(由申请人提供)：目前可用的中和HIV初级分离株的人类单抗(MAbs)只针对HIV包膜糖蛋白的几个区域。一些初级分离株对许多单抗具有抵抗力，但可以被HIV感染者的混合血清中和，这表明可能存在其他尚未鉴定的中和表位。为了开发具有广泛和有效中和活性的新单抗，其活性将补充先前描述的单抗的活性，可用于被动免疫，其表位可被表征并纳入候选HIV疫苗的设计中，我们建议：(A)生产具有针对先前未确定表位的HIV-1初级分离株的有效且广泛的中和活性的人源单抗。现有的人类抗HIV单抗是根据它们的结合活性来选择的。我们建议根据抗HIV单抗的功能，即它们中和含有不同初级分离株env基因的伪病毒粒子的能力来选择抗HIV单抗。(B)描绘用中和屏幕选择的新单抗的中和活性的广度。(C)使用各种免疫学、生化、分子和物理技术来确定和表征最广泛和最有效的单抗所识别的表位。表位测绘技术将包括使用抗原片断文库、随机多肽噬菌体展示文库、表位切除/提取和Arg/Lys化学修饰方法以及X射线晶体分析。这些研究将阐明最好的中和单抗识别的表位的性质，提供关于诱导保护性单抗的表位结构的关键信息。这些数据还将阐明单抗副表位的结构，表位和副表位之间的分子间相互作用，以及不同HIV毒株之间交叉反应的分子基础。(D)使用“集中诱变”技术设计两个选定的单抗，以提高它们的效力和广度，并随后确定这些工程单抗识别的表位的结构。这些研究的结果应该既提供被动免疫的试剂，也提供关于艾滋病毒糖蛋白抗原决定簇性质的数据，这些数据有助于设计将诱导广泛中和抗体的免疫原。

DESCRIPTION (provided by applicant): Currently available human monoclonal antibodies (mAbs) which neutralize primary isolates of HIV are directed against only a few regions of the HIV envelope glycoproteins. Some primary isolates are resistant to many of these mAbs but can be neutralized by pooled sera from HIV-infected individuals, suggesting that there may be additional neutralizing epitopes which have not yet been identified. To develop new mAbs with broad and potent neutralizing activity whose activity will complement those of previously described mAbs, which can be used for passive immunization, and whose epitopes can be characterized and incorporated into the design of candidate HIV vaccines, we propose to: (a) Produce human mAbs with potent and broad neutralizing activity against HIV-1 primary isolates that target previously unidentified epitopes. Existing human anti-HIV mAbs have been selected on the basis of their binding activity. We propose to select anti-HIV mAbs based on their function, i.e., their ability to neutralize pseudovirions containing env genes of various primary isolates. (b) Delineate the breadth of the neutralizing activity of the new mAbs selected with the neutralization screen. (c) Use a variety of immunologic, biochemical, molecular and physical techniques to identify and characterize the epitopes recognized by the broadest and most potent of the mAbs. Epitope mapping techniques will include the use of an antigen fragment library, random peptide phage display libraries, epitope excision/extraction and Arg/Lys chemical modification methods, and X-ray crystallographic analyses. These studies will elucidate the nature of the epitopes recognized by the best of the neutralizing mAbs, providing critical information about the structure of epitopes that induce protective Abs. These data will also elucidate the structure of the mAb paratopes, the intermolecular interactions between epitopes and paratopes, and the molecular basis for the cross-reactivity between diverse strains of HIV. (d) Use a "focused mutagenesis" technique to engineer two selected mAbs in order to improve their potency and breadth, and subsequently determine the structure of the epitopes recognized by these engineered mAbs. The results of these studies should provide both reagents for passive immunization and data on the nature of antigenic determinants of HIV glycoproteins useful for designing immunogens that will induce broadly neutralizing Abs.