A T-independent pathway of B cell responses to oligomannosyl antigens of HIV-1

B 细胞对 HIV-1 寡甘露糖基抗原反应的 T 依赖性途径

• 批准号: 8703221
• 负责人: DENONG WANG
• 金额: $ 75.09万
• 依托单位: SRI INTERNATIONAL
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-13 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8703221
• 关键词: Antibodies; Antibody Formation; Antibody Repertoire; Antigens; B cell repertoire; B-Cell Activation; B-Lymphocyte Subsets; B-Lymphocytes; Binding; Blood Circulation; C-Type Lectins; CD19 gene; CD209 gene; Carbohydrates; Cell Lineage; Cells; Development; Dimensions; Epitopes; Fluorescence-Activated Cell Sorting; Glycoproteins; Greater sac of peritoneum; HIV; HIV Envelope Protein gp120; HIV-1; Human; Hybridomas; Immunization; Immunoglobulin G; Immunoglobulin M; Infection; Mannose; Modeling; Monoclonal Antibodies; Mus; PTPRC gene; Pathway interactions; Phenotype; Polysaccharides; Population; Production; Receptors, Antigen, B-Cell; Research Personnel; Role; Signal Transduction; Specificity; Spleen; Staining method; Stains; Surface; Technology; Tissues; Vaccines; Virion; antigen binding; base; congenic; defined contribution; design; human subject; humanized monoclonal antibodies; interest; mouse model; neutralizing antibody; novel; pathogen; peripheral blood; receptor binding; research study; response; sugar; vaccination strategy

DESCRIPTION (provided by applicant): Discovery of a specific oligomannose cluster as the epitope of a broadly HIV-1 neutralizing antibody (2G12) has stimulated substantial interest in carbohydrate-based HIV-1 vaccines. Recently, we identified a significant population of Man9-cluster-binding B cells (BMan9+) in the naive B cell repertoires. In human peripheral blood, this population constitutes approximately 12% CD19+CD45+ B cells. Similarly, BMan9+ cells represent 10-12% of B-1a (CD19+CD5+) B cells in the mouse peritoneal cavity (PerC). Using carbohydrate microarrays to screen anti-glycan antibodies in human blood circulation, we revealed that significant amounts of anti-Man9-cluster antibodies (IgM and IgG isotypes) are present in both HIV-1 infected and non-infected human subjects. However, the levels of IgG antibodies to Man9-cluster antigen are markedly increased in the HIV-1 infected subjects. These findings suggest that there is an evolutionally conserved BMan9+ cell population present in the pre-existing B cell repertoires that is readily reactive with HIV-1 carbohydrates. Since thi population of antigen-binding B cells is extraordinarily larger than the generally observed antigen-specific B cell populations, we propose that these B cells express not only conventional Ig-B cell receptors but also non-Ig-mannose-binding receptor(s), such as DC-SIGN. Upon binding to either soluble gp120 glycoprotein or the native HIV virions, these cells enter into a unique T-independent pathway of B cell activation, i.e., the C-type-lectin-engaged T-independent type 1 response (TI-1c). In this study, we plan to make use of well-established IgH-allotypic mouse models to further characterize the TI-1c pathway of B cell activation and antibody responses to oligomannosyl antigens of HIV-1. Specifically, we will a) characterize the B cell lineage distribution and origin of the BMan9+ cells (Aim 1); b) examine contributions of B-1 and B-2 lineages to production of anti-oligomannose antibodies in the natural antibody repertoires (Aim 2); c) Examine the acquired antibody responses to rationally designed TI-1c oligomannosyl antigens of HIV-1 (Aim 3); and d) Determine the fine specificity and potential HIV-1 neutralization activity of vaccine-elicited anti-Man9-cluster antibodies (Aim 4). In summary, we propose and design experiments to characterize the TI-1c pathway of B cell activation and antibody responses to oligomannosyl antigens of HIV-1. Information obtained by this study is likely instructive to development of novel vaccination strategies against HIV-1 and other pathogens that express oligomannosyl sugar moieties.

描述(由申请人提供)：发现一个特定的寡核苷酸簇作为广泛的HIV-1中和抗体(2G12)的表位，激发了人们对基于碳水化合物的HIV-1疫苗的浓厚兴趣。最近，我们在原始B细胞库中发现了相当数量的结合Man9簇的B细胞(BMan9+)。在人类外周血中，这一群体约占CD19+CD45+B细胞的12%。同样，BMan9+细胞占小鼠腹膜腔内B-1a(CD19+CD5+)B细胞的10-12%。利用碳水化合物芯片筛选人体血液循环中的抗多糖抗体，我们发现在感染和未感染HIV-1的人中都存在大量的抗Man9-簇抗体(IgM和Ig G亚型)。然而，在HIV-1感染者中，抗Man9-簇抗原的抗体水平显著升高。这些发现表明，在现有的B细胞谱系中，存在一个进化上保守的BMan9+细胞群，它很容易与HIV-1碳水化合物反应。由于抗原结合B细胞的数量比通常观察到的抗原特异性B细胞数量要多得多，我们认为这些B细胞不仅表达常规的Ig-B细胞受体，而且还表达非Ig甘露糖结合受体(S)，如DC-SIGN。当这些细胞与可溶性gp120糖蛋白或天然HIV病毒粒子结合后，进入一条独特的T非依赖性B细胞激活途径，即C型凝集素参与的T非依赖性1型反应(TI-1c)。在这项研究中，我们计划利用已建立的高同种异型小鼠模型来进一步表征TI-1c激活B细胞的途径和对HIV-1的寡头节抗原的抗体反应。具体地说，我们将a)确定B细胞谱系的分布和BMan9+细胞的来源(目标1)；b)检测B-1和B-2谱系对天然抗体库中抗寡聚抗体产生的贡献(目标2)；c)检测获得的抗体对合理设计的HIV-1的TI-1c寡聚合体抗原的反应(目标3)；以及d)确定疫苗激发的抗Man9簇抗体(目标4)的良好特异性和潜在的HIV-1中和活性。综上所述，我们建议并设计实验来表征TI-1c激活B细胞的途径和对HIV-1寡核苷酸抗原的抗体反应。这项研究获得的信息可能对开发针对HIV-1和其他表达低聚糖基的病原体的新疫苗策略具有指导意义。