Proteolytic Antibody HIVcides

描述（由申请人提供）：一种用于艾滋病毒预防的特异性、不可逆和具有成本效益的局部杀微生物剂将有助于减缓该流行病的性传播。在这里，我们建议开发能够降解HIV包膜蛋白gp 120的催化抗体作为候选HIV杀剂。这些抗体的有前途的特点是包膜蛋白的永久性破坏，重复使用一个单一的催化剂分子降解数千个gp 120分子，并识别一个保守的gp 120区域，超抗原区域，允许中和不同的HIV毒株。未感染和HIV感染受试者的多克隆抗体研究表明，高水平的蛋白水解和HIV中和活性是伊加类抗体的一个值得注意的特性。在R21项目阶段，提出了我们现有抗体及其单链Fv（scFv）、伊加和IgG变体的表征。现有的抗体通过用亲电子gp 120类似物免疫获得IgG，所述亲电子gp 120类似物诱导具有增强的亲核反应性的抗体，这是催化反应的先决条件。使用亲电子探针的gp 120超抗原位点，获得额外的蛋白水解抗体的scFv构建体克隆从狼疮患者的免疫库，谁往往产生抗体的蛋白水解活性针对gp 120超抗原位点。抗体将在HIV降解效率; HIV中和的特异性、效力和广度;以及在阴道环境中执行这些功能的能力方面进行表征。为了分离新型改良抗体，我们将在R21项目阶段筛选来自HIV阴性和HIV阳性受试者的唾液和血清IgA的蛋白水解和HIV中和活性。在R33阶段，将通过基于亲电子gp 120肽类似物的共价结合的细胞分级分离从淋巴细胞克隆具有所需性质的单克隆IgA，所述亲电子gp 120肽类似物的共价结合是与蛋白水解抗体产生细胞相关的性质。将在R33阶段使用SHIV-猕猴感染模型获得体内抗体效力的原理证明。还将在模拟性交后阴道环境的条件下检查Ab作为杀微生物剂赋形剂制剂的体外活性。这些研究可能会确定蛋白水解抗体适合进一步发展为一个局部HIV杀。

DESCRIPTION (provided by applicant): A specific, irreversible and cost-effective topical microbicide for HIV prophylaxis will help slow sexual transmission of the pandemic. Here, we propose the development of catalytic antibodies capable of degrading the HIV envelope protein gp120 as candidate HIVcides. The promising features of the antibodies are the permanent destruction of the envelope protein, reuse of a single catalyst molecule to degrade thousands of gp120 molecules and the recognition of a conserved gp120 region, the superantigen region, permitting neutralization of diverse HIV strains. Polyclonal antibody studies from uninfected and HIV infected subjects indicated that high level proteolytic and HIV neutralizing activities is a noteworthy property of IgA class antibodies. In the R21 project phase, characterization of our existing antibodies and their single chain Fv (scFv), IgA and IgG variants is proposed. The existing antibodies were obtained as IgGs by immunization with an electrophilic gp120 analog that induces antibodies with enhanced nucleophilic reactivity, a prerequisite for the catalytic reaction. Using an electrophilic probe to the gp120 superantigen site, additional proteolytic antibodies were obtained as scFv constructs cloned from the immune repertoire of lupus patients, who tend to produce antibodies with proteolytic activity directed to the gp120 superantigen site. The antibodies will be characterized with respect to HIV degrading efficiency; specificity, potency and breadth of HIV neutralization; and the ability to perform these functions in the vaginal milieu. To isolate novel, improved antibodies, we will screen the proteolytic and HIV neutralizing activity of salivary and serum IgAs from HIV-negative and HIV-positive subjects in the R21 project phase. In the R33 phase, monoclonal IgAs with the desired properties will be cloned from lymphocytes by cell-fractionation based on covalent binding of an electrophilic gp120 peptide analog, a property associated with proteolytic antibody-producing cells. Proof-of-principle for in vivo antibody efficacy will be obtained in the R33 phase using the SHIV-macaque model of infection. The Abs will also be examined for activity in vitro as microbicide excipient formulations under conditions simulating the vaginal environment following sexual intercourse. These studies may identify proteolytic antibodies suitable for further development as a topical HIVcide.