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: 8933717
• 负责人: Michael Paul Cancro
• 金额: $ 72.86万
• 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/8933717
• 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; Health; 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; Sorting - Cell Movement; Specificity; Staging; 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; 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（由申请人提供）：尽管在数量上对HIV-1有强大的体液免疫反应，但预防是罕见的，因为在自然免疫或疫苗接种后，广泛中和的抗体是罕见的。越来越多的证据表明，这反映了在B细胞发育或激活期间施加的检查点广泛中和反应所需的B细胞的反选择。这些观察结果预测，放松B细胞反选择应该改变hiv特异性反应的质量，并建立具有预防潜力的基因库，但这一预测尚未得到直接测试。细胞因子BLyS在两个检查点调节B细胞的选择：首先在过渡到成熟的免疫前B细胞发育阶段；然后在生发中心的活化B细胞中。重要的是，在HIV-1包膜免疫之前用BLyS治疗小鼠，可以提高小鼠对更广泛的中和活性做出反应的频率。总之，这些观察结果使我们能够详细研究过渡和/或生发中心检查点的放松选择如何影响广泛中和反应的能力。在Aim 1中，我们将确定BLyS的放松过渡选择是否建立了更能广泛中和的免疫前库。我们将通过分析过渡区、滤泡区和边缘区B细胞亚群的库组成和多样性来实现这一目标，其次是单细胞