Developing Broadly Neutralizing MAbs for an HIV Vaccine

描述(由申请人提供)：开发有效的艾滋病毒/艾滋病疫苗的首要任务是激发广泛的中和抗体，以防止来自大量初级分离株的艾滋病毒-1感染。从HIV感染者中分离到的几株单抗包括lgG1b12、2G12、2F5和4E10具有广泛的中和活性，但这种有效的单抗还没有在动物身上开发出来。单抗2G12识别gp120上的高甘露糖多聚糖，特别是几个Manalpha1，2-Man结构的簇。这种末端α-1，2-连接的甘露糖位于Man8和Man9糖链上，也是一种有效的HIV抑制剂氰基韦林-N的高亲和力结合位点。高甘露糖在所有HIV-1原始分离株的gp120包膜蛋白上高度保守，并被所有测试的HIV-1、HIV-2、SIV和SIV毒株用来结合树突状细胞。因此，高甘露聚糖可能成为广泛开发HIV-1中和抗体的新靶点。 假设：将gp120上的所有多糖转换为Man8和Man9将显著增加Manalpha1，2-Man表位的数量，并创建由两个或更多高甘露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潜力来刺激Manalpha1，2-Man特异性抗体。经过一系列筛选，将开发出能够中和多种HIV-1毒株的单抗。 具体目的：(1)制备主要含有Man8和Man9的HIV-1 gp120，确定其糖类，并与哺乳动物细胞中的gp120进行抗原性比较。(2)制备gp120-破伤风类毒素结合物，免疫小鼠，筛选不同亚型gp120的交叉反应抗体，检测gp120-DC-SIGN结合的抑制作用，并测定中和活性。(3)开发Manalpha1，2-Man特异性单抗，识别来自不同分支的gp120蛋白，并有效中和广泛的HIV-1初级分离株。 在这项研究完成后，我们将最终验证新的抗原。如果成功，该抗原将成为一种新的艾滋病毒候选疫苗，单抗将标志着艾滋病毒疫苗设计的一个里程碑。它们将进一步导致开发一种针对众多艾滋病毒-1初级分离株的有效疫苗，供全球普通人群使用。

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.