Molecular Regulation of Germinal Center B Lymphocytes

生发中心 B 淋巴细胞的分子调控

• 批准号: 8649227
• 负责人: Alexander Gitlin
• 金额: $ 4.77万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8649227
• 关键词: Address; Adoptive Transfer; Affinity; Amino Acids; Animals; Antibodies; Antibody Affinity; Antigen-Antibody Complex; Antigens; Area; B-Lymphocytes; Binding; Biology; CD4 Positive T Lymphocytes; Cell Count; Cells; Complex; Cytoplasmic Tail; Endocytosis; Event; Flow Cytometry; Follicular Dendritic Cells; Germinal Center B-Lymphocyte; Goals; Humoral Immunities; IgG1; Immune response; Immunization; Immunoglobulin Class Switching; Immunoglobulin G; Immunoglobulin M; Immunoglobulin Somatic Hypermutation; Immunoglobulin Switch Recombination; Immunoglobulin Variable Region; Immunoglobulins; Immunology; Infection; Institutes; Knock-in Mouse; Life; Light; Lymphoid; Major Histocompatibility Complex; Measures; Memory; Molecular; Molecular Genetics; Mus; Mutate; Organ; Peptides; Plasma Cells; Play; Process; Proliferating; Property; Protocols documentation; Public Health; Reaction; Receptor Signaling; Receptors, Antigen, B-Cell; Regulation; Research; Role; Signal Transduction; Structure of germinal center of lymph node; System; T-Lymphocyte; Techniques; Time; Transgenic Mice; Vaccine Design; Vaccines; activation-induced cytidine deaminase; antigen binding; base; chimeric antibody; insight; intravital imaging; migration; mouse model; mutant; novel; novel vaccines; pathogen; public health relevance; recombinase; response; vaccine development; Address; Adoptive Transfer; Affinity; Amino Acids; Animals; Antibodies; Antibody Affinity; Antigen-Antibody Complex; Antigens; Area; B-Lymphocytes; Binding; Biology; CD4 Positive T Lymphocytes; Cell Count; Cells; Complex; Cytoplasmic Tail; Endocytosis; Event; Flow Cytometry; Follicular Dendritic Cells; Germinal Center B-Lymphocyte; Goals; Humoral Immunities; IgG1; Immune response; Immunization; Immunoglobulin Class Switching; Immunoglobulin G; Immunoglobulin M; Immunoglobulin Somatic Hypermutation; Immunoglobulin Switch Recombination; Immunoglobulin Variable Region; Immunoglobulins; Immunology; Infection; Institutes; Knock-in Mouse; Life; Light; Lymphoid; Major Histocompatibility Complex; Measures; Memory; Molecular; Molecular Genetics; Mus; Mutate; Organ; Peptides; Plasma Cells; Play; Process; Proliferating; Property; Protocols documentation; Public Health; Reaction; Receptor Signaling; Receptors, Antigen, B-Cell; Regulation; Research; Role; Signal Transduction; Structure of germinal center of lymph node; System; T-Lymphocyte; Techniques; Time; Transgenic Mice; Vaccine Design; Vaccines; activation-induced cytidine deaminase; antigen binding; base; chimeric antibody; insight; intravital imaging; migration; mouse model; mutant; novel; novel vaccines; pathogen; public health relevance; recombinase; response; vaccine development

DESCRIPTION (provided by applicant): Germinal centers (GCs) form transiently in secondary lymphoid organs following immunization or infection and are central in providing humoral immunity. Within the GC, antigen-specific B lymphocytes express activation-induced cytidine deaminase (AID), inducing somatic hypermutation (SMH) and class switch recombination (CSR). These processes randomly mutate the immunoglobulin locus and switch antibody isotype, respectively. Competitive selection ensues among mutant GC B cells, with high affinity B cells undergoing selective expansion and differentiating into memory or plasma cells. Although the GC has long been studied, the events controlling selection of high affinity B cells remain obscure. The GC is subdivided into two anatomically and functionally distinct regions, the light (LZ) and dark zones (DZ). In the LZ, B cells bind antigen, retained as immune complexes on follicular dendritic cells (FDCs), in proportion to their affinity and process it for presentation to CD4+ T cells as peptide bound to major histocompatibility complex II (pMHCII). In this manner, high affinity GC B cells are selected based on pMHCII and T cell help, but the mechanisms by which this occurs are not known. Furthermore, a direct role for the B cell receptor (BCR) in GC selection, in addition to endocytosing antigen, has been suggested but never elucidated. This issue is further complicated by ongoing isotype switching in the GC, which changes the BCR signaling capacity. This proposal seeks to analyze how pMHCII levels and isotype-specific BCR signal transduction regulate GC B cell selection mechanisms. Toward the first goal, an antigen delivery system will be used that can modulate pMHCII levels on a subset of GC B cells in a temporally controlled manner. Toward the second goal, novel mice will be generated in which the isotype of the BCR can be switched through cre recombinase, independently of antibody affinity and somatic hypermutation. These problems, central to GC biology and the humoral immune response, will be addressed through a combination of mouse molecular genetics, traditional immunology techniques, flow cytometry, and multiphoton intravital imaging of live animals undergoing GC responses.

描述（由申请人提供）：免疫或感染后，在次级淋巴机器人中瞬时形成生发中心（GCS），在提供体液免疫方面是核心。在GC中，抗原特异性B淋巴细胞表达激活诱导的胞苷脱氨酶（AID），诱导体形超突变（SMH）和类开关重组（CSR）。这些过程分别随机突变免疫球蛋白基因座和开关抗体同种型。在突变GC B细胞中随之而来的竞争选择，高亲和力B细胞经历了选择性扩张，并区分了记忆或浆细胞。尽管长期研究了GC，但控制高亲和力B细胞选择的事件仍然晦涩难懂。 GC细分为两个解剖学和功能不同的区域，即光（LZ）和黑暗区域（DZ）。在LZ中，B细胞结合抗原，作为卵泡树突状细胞（FDC）的免疫复合物保留，与其亲和力成正比，并将其处理给CD4+ T细胞，作为与主要组织相容性复合物II（PMHCII）结合的肽。以这种方式，根据PMHCII和T细胞帮助选择了高亲和力GC B细胞，但是发生这种情况的机制尚不清楚。此外，除了内吞抗原外，B细胞受体（BCR）在GC选择中的直接作用已经提出，但从未阐明。 GC中持续的同种型切换使该问题更加复杂，这会改变BCR信号传导能力。该建议旨在分析PMHCII水平和同型特异性BCR信号转导如何调节GC B细胞选择机制。朝向第一个目标，将使用一个抗原递送系统，可以以时间控制的方式在GC B细胞的子集上调节PMHCII水平。朝向第二个目标，将产生新的小鼠，其中可以通过CRE重组酶切换BCR的同型，而与抗体亲和力和体细胞超成名无关。这些问题是GC生物学和体液免疫反应的核心，将通过小鼠分子遗传学，传统的免疫学技术，流式细胞仪和经历GC反应的活动物的多光经体成像的结合来解决。