HIV-2 Env Variable Loop Deletions as HIV-1 Vaccines

HIV-2 Env 可变环缺失作为 HIV-1 疫苗

• 批准号: 7035890
• 负责人: GEORGE LIN
• 金额: $ 28.12万
• 依托单位: BIOLOGICAL MIMETICS, INC.
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2007-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7035890
• 关键词: AIDS vaccines; CD4 molecule; HIV envelope protein gp120; chemokine receptor; gene deletion mutation; genetic manipulation; human immunodeficiency virus 1; human immunodeficiency virus 2; neutralizing antibody; protein structure function; receptor binding; virus envelope

DESCRIPTION (provided by applicant): HIV is extremely adept in evading humoral immunity. Although neutralizing antibodies (NAbs) are produced to the viral envelope glycoprotein (Env), they are characteristically directed to hypervariable loops on gp120 (V1/V2 and V3), which can tolerate extensive genetic variation. Thus, these NAbs are generally "type specific" and not broadly neutralizing. In addition, the variable loops protect highly conserved functional domains on the gp120 core, i.e. binding sites for CD4 and chemokine receptors (CCR5 and CXCR4). Using CD4-independent Envs, we have derived replication competent variants of HIV-2 that lack V1/V2 and V3 hypervariable loops. Although viruses without V1/V2 have been described for HIV-1 and SIV, no virus to date has tolerated deletions in V3; V3 has been considered indispensable for Env function and coreceptor binding. Given the role of V1/V2 and V3 in protecting core domains from humoral immune responses, we hypothesize that Envs from these "minimized," loop-deleted viruses may have the potential to elicit novel antibodies to conserved and functional epitopes on gp120. Moreover, we hypothesize that Envs from CD4-independent HIV isolates represent a transition state in the Env-fusion cascade with exposed receptor binding regions and decreased conformational flexibility, properties that may be desirable in generating neutralizing antibodies. Thus, CD4-independent Envs with strategic removal of structures prohibitory to effective neutralizing antibody elicitation without altering Env function may allow derivation of a better immunogen that is able to elicit broadly neutralizing antibodies and "immune refocus" these antibodies towards key functional regions on Env. Our work has been focused on extending our findings to HIV-1 Envs such that they may be applied to HIV-1 vaccine development. Instead of taking a direct approach of generating HIV-1 Envs with hypervariable loop deletions, we explore here the feasibility of introducing HIV-1 converting mutations at receptor binding regions and/or epitopes for key anti-HIV-1 NAbs into our fully-functional hypervariable loop deleted HIV-2 Envs to generate functional, loop deleted "HIV-1 like" Envs for future HIV-1 vaccine studies. Two Specific Aims are proposed: #1) engineer HIV-1 converting mutations into wildtype HIV-2/vcp Env and functional, hypervariable loop deleted derivatives and assess for retention of functionality and #2) determine the reactivity of key anti-HIV-1 neutralizing MAbs (b12, CD4i MAbs, 2F5, and 4E10) to wildtype HIV-2/vcp Env and hypervariable loop derivatives with HIV-1 converting mutations.

描述（由申请人提供）：HIV非常擅长逃避体液免疫。尽管对病毒包膜糖蛋白（ENV）产生中和抗体（NAB），但它们的特征是在GP120（V1/V2和V3）上可耐受性遗传的遗传变异。因此，这些NAB通常是“特定类型的”，而不是广泛中和。此外，可变环保护GP120核心上高度保守的功能域，即CD4和趋化因子受体的结合位点（CCR5和CXCR4）。使用与CD4无关的ENV，我们得出了缺乏V1/V2和V3 Hypervariable循环的HIV-2的复制竞争型变体。尽管已经描述了HIV-1和SIV的没有V1/V2的病毒，但迄今为止，没有病毒可以忍受V3中的缺失。 V3被认为是ENV函数和共感受器结合必不可少的。鉴于V1/V2和V3在保护核心结构域免受体液免疫反应中的作用，我们假设从这些“最小化”中的ENV中，环状骨骼缺失的病毒可能有可能引起对GP120上保守和功能性表位的新型抗体。此外，我们假设来自CD4独立的HIV分离株的ENV代表了带有裸露受体结合区域的Envusion Fusion Cascade中的过渡态，并降低了构象柔韧性，这些特性在产生中和中和抗体时可能是可取的。因此，与CD4无关的Envs具有战略性去除结构禁止，以有效中和中和抗体启发而不改变ENV功能，可以允许衍生出更好的免疫原，该免疫原能够引起广泛中和的抗体，并“免疫重新集中”这些抗体对关键功能的ENV上的关键功能。我们的工作一直致力于将我们的发现扩展到HIV-1 ENV，以便将其应用于HIV-1疫苗的开发。 Instead of taking a direct approach of generating HIV-1 Envs with hypervariable loop deletions, we explore here the feasibility of introducing HIV-1 converting mutations at receptor binding regions and/or epitopes for key anti-HIV-1 NAbs into our fully-functional hypervariable loop deleted HIV-2 Envs to generate functional, loop deleted "HIV-1 like" Envs for future HIV-1 vaccine studies. Two Specific Aims are proposed: #1) engineer HIV-1 converting mutations into wildtype HIV-2/vcp Env and functional, hypervariable loop deleted derivatives and assess for retention of functionality and #2) determine the reactivity of key anti-HIV-1 neutralizing MAbs (b12, CD4i MAbs, 2F5, and 4E10) to wildtype HIV-2/vcp Env and hypervariable带有HIV-1转换突变的循环衍生物。