Developing Broadly Neutralizing MAbs for an HIV Vaccine

描述（由申请方提供）：在开发有效的HIV/AIDS疫苗的过程中，激发广泛中和抗体以预防来自大量原始分离株的HIV-1感染是重中之重。从HIV感染的人中分离的几种MAb，包括IgG 1b 12、2G 12、2F 5和4 E10，具有广泛的中和活性，但这种有效的MAb尚未在动物中开发。MAb 2G 12识别gp 120上的高甘露糖聚糖，特别是一簇几个Manalpha 1，2-Man结构。Man 8和Man 9聚糖上的这种末端α 1，2-连接的甘露糖也是HIV的有效抑制剂氰威-N的高亲和力结合位点。高甘露糖聚糖在所有HIV-1原代分离株的gp 120 env蛋白上高度保守，并被所有检测的HIV-1、HIV-2、SIV和SHIV毒株用于结合树突状细胞。因此，高甘露糖聚糖可能是开发广泛的HIV-1中和抗体的新靶点。 假设：将gp 120上的所有聚糖转化为Man 8和Man 9将显著增加Manalpha 1，2-Man表位的数量，并产生由两个或更多个高甘露糖聚糖组成的更多样化的构象表位阵列。这种新形式的抗原具有更大的刺激Manalpha 1，2-Man特异性抗体的潜力。经过一系列筛选，将开发出能够中和多种HIV-1分离株的单克隆抗体。 具体目标：（1）生产主要含有Man 8和Man 9的HIV-1 gp 120，确认碳水化合物的类型，并与来自哺乳动物细胞的gp 120比较其抗原性。(2)制备gp 120-破伤风类毒素缀合物，免疫小鼠并筛选免疫血清中针对不同亚型gp 120的交叉反应性抗体，检查gp 120-DC-SIGN结合的抑制，并测量中和活性。(3)开发Manalpha 1，2-Man特异性单克隆抗体，识别来自不同进化枝的gp 120蛋白，并有效中和广泛的HIV-1原代分离株。 完成本研究后，我们将最终验证新抗原。如果成功，该抗原将成为一种新的HIV疫苗候选物，单克隆抗体将标志着HIV疫苗设计的里程碑。它们将进一步导致针对许多HIV-1主要分离株的有效疫苗的开发，用于全球普通人群。

DESCRIPTION (provided by applicant): Eliciting broadly neutralizing antibodies to prevent HIV-1 infection from a large diversity of primary isolates is a top priority in the development of an effective HIV/AIDS vaccine. Several MAbs isolated from HIV infected humans including lgG1b12, 2G12, 2F5 and 4E10 have broad neutralizing activity, but such potent MAbs have yet to be developed in animals. The MAb 2G12 recognizes the high mannose glycans on gp120, specifically a cluster of several Manalpha1, 2-Man structures. Such terminal alpha1,2-linked mannoses on Man8 and Man9 glycans are also the high affinity binding sites for a potent inhibitor of HIV, cyanovirin-N. High mannose glycans are highly conserved on the gp120 env protein of all HIV-1 primary isolates, and are used by all tested HIV-1, HIV-2, SIV and SHIV strains to bind dendritic cells. Therefore, the high mannose glycans could be novel targets for developing broadly HIV-1 neutralizing antibodies. HYPOTHESES: Converting all of the glycans on gp120 to Man8 and Man9 will significantly increase the number of Manalpha1, 2-Man epitopes, and create a more diverse array of conformational epitopes consisting of two or more high-mannose glycans. This novel form of antigen has a greater potential to stimulate Manalpha1, 2-Man-specific antibodies. After a series of screenings, MAbs that are able to neutralize a large diversity of HIV-1 isolates will be developed. SPECIFIC AIMS: (1) Produce HIV-1 gp120s that contain mainly Man8 and Man9, confirm the type of carbohydrate and compare their antigenicity with gp120 from mammalian cells. (2) Prepare gp120-tetanus toxoid conjugates, immunize mice and screen immune sera for cross-reactive antibodies to gp120s from different subtypes, examine inhibition of gp120-DC-SIGN binding, and measure neutralizing activities. (3) Develop Manalpha1, 2-Man-specific MAbs that recognize gp120 proteins from different clades and potently neutralize a broad range of HIV-1 primary isolates. After completion of this study we will have conclusively validated the novel antigens. If successful, the antigen would be a novel HIV vaccine candidate and the MAbs would signify a milestone in HIV vaccine design. They will further lead to the development of an efficient vaccine against numerous HIV-1 primary isolates for use in the general population globally.