Mechanistic studies of BLyS-mediated modulation in HIV-1 Env-specific antibody responses

BLyS 介导的 HIV-1 Env 特异性抗体反应调节机制研究

• 批准号: 9212095
• 负责人: Michael Paul Cancro
• 金额: $ 68.66万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-10 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9212095
• 关键词: Antibodies; Antibody Response; B-Cell Activation; B-Cell Development; B-Lymphocyte Subsets; B-Lymphocytes; Binding; Cell Maturation; Cells; Clone Cells; Development; Disadvantaged; Frequencies; HIV; HIV vaccine; HIV-1; Immune response; Immunization; Immunoglobulin Somatic Hypermutation; Immunoglobulin Variable Region; Macaca mulatta; Mediating; Memory B-Lymphocyte; Mus; Mutate; Pattern; Positioning Attribute; Prophylactic treatment; Reaction; Recruitment Activity; Research; Specificity; Structure of germinal center of lymph node; TALL-1 protein; Testing; Vaccination; Work; cytokine; env Gene Products; improved; in vivo; neutralizing antibody; nonhuman primate; prophylactic; public health relevance; response

 DESCRIPTION (provided by applicant): Despite quantitatively robust humoral immune responses to HIV-1, prophylaxis is rare because broadly neutralizing antibodies are uncommon after natural immunization or vaccination. Increasing evidence suggests this reflects the counterselection of B cells needed for broadly neutralizing responses at checkpoints imposed during B cell development or activation. These observations predict that relaxing B cell counterselection should alter the quality of HIV-specific responses and establish repertoires with prophylactic potential, but this prediction has not been directly tested. The cytokine BLyS modulates B cell selection at two checkpoints: first at the transitional to mature preimmune B cell developmental step; and then among activated B cells in the germinal center. Importantly, treating mice with BLyS prior to HIV-1 envelope immunization yields an increased frequency of mice responding with broader neutralizing activity. Together, these observations position us for detailed study of how relaxed selection at the transitional and/or germinal center checkpoints impacts the ability to mount broadly neutralizing responses. In Aim 1, we will determine whether relaxing transitional selection with BLyS establishes a preimmune repertoire more capable of broad neutralization. We will accomplish this through analyses of repertoire composition and diversity in the transitional, follicular and marginal zone B cell subsets, followed by single-cell cloning and re-expression of antibodies to assess HIV neutralizing capacity. In Aim 2, we will use a similar strategy to determine whether surplus BLyS alters germinal center selection, and allows somatically mutated germinal center B cells capable of broadly neutralizing responses to persist and enter memory B cell pools. We will compare GC and memory B cells from mice treated with BLyS prior to immunization with Env, or from mice treated with exogenous BLyS in the early stages of GC formation after Env immunization. In Aim 3, we will extend our findings to nonhuman primates, by determining whether rhesus macaques show similar enlargement of TR and FO pools after BLyS treatment, and whether BLyS treatment prior to Env vaccination improves neutralizing antibody breadth.

 描述（由应用提供）：尽管对HIV-1进行了定量健壮的体液免疫调查，但预防性很少，因为自然免疫抑制或疫苗接种后广泛中和抗体并不常见。越来越多的证据表明，这反映了在B细胞发育或激活过程中施加的检查点上大规模中和反应所需的B细胞的反选择。这些观察结果预测，放松的B细胞反选择应改变HIV特异性反应的质量，并建立具有预防潜力的曲目，但该预测尚未直接测试。细胞因子Blys在两个检查点处调节B细胞的选择：首先在过渡到成熟的免疫前B细胞发育步骤中；然后在生殖中心的活化的B细胞中。重要的是，在HIV-1包膜免疫抑制之前用Blys处理小鼠会导致小鼠随着更广泛的中和活性反应的频率增加。这些观察结果共同为我们定位，以详细研究过渡和/或生发中心检查点的放松选择如何影响安装广泛中和反应的能力。在AIM 1中，我们将确定放松的过渡选择是否会建立更广泛神经化的免疫前曲目。我们将通过分析过渡，卵泡和边缘区B细胞子集的曲目组成和多样性的分析来实现这一目标，然后是单细胞 抗体评估HIV中和能力的克隆和重新表达。在AIM 2中，我们将使用类似的策略来确定多余的Blys是否改变了生发中心的选择，并允许体形突变的生发中心B细胞能够广泛中和响应以持续存在并进入记忆B细胞池。我们将比较在与Env进行免疫之前用BLYS处理的小鼠的GC和记忆B细胞，或者在ENV免疫抑制后GC形成的早期阶段在GC形成的早期用外源性脂肪的小鼠进行比较。在AIM 3中，我们将通过确定恒河猕猴在Blys处理后是否显示出类似的TR和FO池的扩张，以及在ENV疫苗接种之前是否可以改善中和抗体的宽度来改善BLYS治疗后，将我们的发现扩展到非人类初级。