Plant-derived HIV neutralizing mAbs for passive immunotherapy in newborn macaques

 描述（由申请人提供）：针对 HIV-1 的高效广泛中和抗体 (bnAb) 的鉴定，以及被动给药后成功预防 SHIV 感染，增加了采用免疫治疗策略来预防和治疗 HIV-1 感染的可能性。然而，虽然广泛而有效的中和活性是一个重要的先决条件，但良好的循环稳定性和无免疫原性等体内特性对于开发人类治疗方法同样重要。在之前的 I 期和 II 期研究中，第一代 bnAb 和更新的强效高度突变 bnAb 10-1074、NIH45-46G54W、10E8、PGT121、PGT128、PGT145、PGT135、PG9、PG16、VRC01 和 b12 的糖型均已通过农杆菌介导的瞬时产生转染本塞姆氏烟草并评估中和活性以及在猕猴中给药后的情况。迄今为止的结果表明，(i) VL 结构域内的 N-聚糖会损害植物来源的 bnAb 的血浆稳定性，并且 (ii) 虽然 PGT121 和 b12 在多次注射后在猕猴中没有表现出免疫原性，但令人惊讶的是，VRC01、10-1074 和 NIH45-46G54W 在第二次注射后引发了高效价的抗独特型抗体，该抗体特异性结合所施用的 bnAb 或(iii) 两种鸡尾酒（VRC01、10-1074、b12 和 10E8）以及单一 PGT121 在攻击前和攻击后静脉内或皮下注射均可保护成年猕猴。这些结果构成了当前IIB期提案的双重方法的基础，即通过以下方式开发有效的bnAb混合物：（i）在猕猴中进行针对SHIV攻击的围产期保护研究，更接近地模拟母婴传播（MTCT）（ii）延长其循环保留时间，以及（iii）识别这些高度突变的bnAb上的T细胞表位，这些表位有助于其免疫原性，并可能损害其价值HIV-1 的预防和治疗。此外，本研究中15种广泛中和植物源性HIV单克隆抗体的快速生产凸显了瞬时植物系统在速度和多功能性、无病原体性质和低技术要求方面的独特优势；特别是在从“克隆到临床前保护研究”的早期发展阶段。

 DESCRIPTION (provided by applicant): The identification of highly potent broadly neutralizing antibodies (bnAbs) against HIV-1, and success in preventing SHIV infection following their passive administration, have increased the likelihood that immunotherapeutic strategies can be adopted to prevent and treat HIV-1 infection. However, while broad and potent neutralizing activity is an essential prerequisite, in vivo properties such as good circulatory stability and no-immunogenicity are equally critical for developing a human treatment. In the previous Phase I and Phase II studies, glycoforms of both first generation bnAbs and more recent potent highly mutated bnAbs 10-1074, NIH45-46G54W, 10E8, PGT121, PGT128, PGT145, PGT135, PG9, PG16, VRC01 and b12 have been produced by Agrobacterium-mediated transient transfection of Nicotiana benthamiana and assessed neutralizing activity and following admin- istration in macaques. The results to date indicate that (i) N-glycans within the VL domain impair plasma stability of plant-derived bnAbs and (ii) while PGT121 and b12 exhibit no immunogenicity in macaques after multiple injections, surprisingly VRC01, 10-1074 and NIH45-46G54W elicit high titer anti-idiotypic antibodies following a second injection which specifically bind the administered bnAb or a close family member, and inhibit the bnAb in neutralization assays (iii) both cocktails (VRC01, 10-1074, b12 and 10E8) as well as single PGT121 delivered either intravenously or subcutaneously both pre-and post-challenge administration can protect adult macaques. These results form the basis of the current Phase IIB proposal's dual approach to develop an efficacious bnAb cocktail by (i) performing perinatal protection studies in macaques against SHIV challenge which more closely mimic mother-to-child-transmission (MTCT) (ii) to extend their circulatory retention time and (iii) to identify the T cell epitopes on these highly mutated bnAbs which contribute to their immunogenicity and which could potentially compromising their value for prophylaxis and therapy of HIV-1. In addition, the rapid production of 15 broadly neutralizing plant-derived HIV mAbs in the current study highlights the unique advantages of the transient plant system in terms of speed and versatility, pathogen- free nature and low-tech requirements; particularly in the early developmental stages from "cloning to preclinical protection studies".