Characterization of an Alternative Adaptive Immune System in Hagfish

盲鳗替代适应性免疫系统的表征

基本信息

批准号：
9040973
负责人：
Max Dale Cooper
金额：
$ 29.64万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-08-01 至 2017-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9040973
关键词：
Adult Allogenic Antibodies Antibody Repertoire Antibody Response Antigen Receptors Antigens B-Lymphocytes Blood Cell Lineage Cells Computer Analysis Cytosine deaminase DNA cassette Development Diagnostic Reagent Discrimination Drug or chemical Tissue Distribution Eels Elements Evolution Exhibits Fishes Gene Expression Gene Expression Profile Genes Genetic Programming Germ Lines Gills Goals Hagfish Health Hemorrhage Immune Immune response Immune system Immunization Immunoglobulin Variable Region Immunoglobulins In Vitro Infectious Agent Jaw Lampreys Learning Leucine-Rich Repeat Libraries Lymphocyte Lymphocyte Activation Mature Lymphocyte Mitogens Molecular Molecular Probes Molecular Profiling Monoclonal Antibodies Names Nomenclature Pathway interactions Patients Pilot Projects Plasma Population Proteins Protocols documentation Receptor Gene Receptors, Antigen, B-Cell Sequence Analysis Site Specificity Structure Surface Surveys T-Cell Receptor T-Lymphocyte Technology Testing Thymus Gland Vertebrates Wit Yeasts antigen binding antigen processing base cancer cell comparative hematopoietic tissue in vivo insight microbial novel pathogen plasma cell differentiation receptor research study response screening time interval

项目摘要

DESCRIPTION (provided by applicant): Widely considered the most basal vertebrates alive today, hagfishes represent a pivotal point in evolution and thus offer a key piece to the puzzle of how our lymphocyte-based adaptive immune system evolved. An alternative adaptive immune system has been identified recently in the two extant jawless vertebrates, lampreys and hagfish, which last shared a common ancestor ~480 million years ago. While immunoglobulin- based antigen receptors are used by jawed vertebrates, jawless vertebrates instead use leucine-rich repeat (LRR)-based variable lymphocyte receptors (VLR) of three types to recognize antigens. VLRA and VLRC are assembled in the lamprey thymus-equivalent gill region by two lymphocyte lineages that resemble mammalian ab and gd T cell lineages. VLRB is assembled in hematopoietic tissues by B-like lymphocytes, which undergo plasma cell differentiation and secrete multivalent VLRB antibodies with structural features and antigen specificities that offer significant advantages for biomedical uses. Hagfish cells expressing the different VLRs have not yet been identified or functionally defined. To elucidate the hagfish immune system, monoclonal antibodies specific for invariant portions of their three VLRs have been made for use in analyzing development, distribution and function of hagfish lymphocytes, with particular emphasis on defining the structure and antigen-binding specificities of hagfish VLRB antibodies. The first aim is to define the tissue distribution and gene expression patterns of hagfish VLRA +, VLRB+ and VLRC+ lymphocytes. A principle objective here is to identify the primary sites in which VLRA and VLRB assembly occurs versus secondary sites in which mature lymphocytes undergo proliferation and differentiation. The second aim is to characterize hagfish lymphocyte responses to antigens, allogeneic cells, and mitogens. To determine why hagfish exhibit weak humoral immune responses to immunization, yet have an abundance of circulating VLRB proteins, these experiments will employ refined immunization protocols that elicit robust VLRB antibody responses in lampreys. Pilot studies imply that the hagfish VLRA+ and VLRC+ lymphocytes preferentially respond to cells from other lampreys, and experiments are proposed to find the 'allo-recognition elements' of jawless vertebrates. The third specific aim is to construct yeast surface display libraries for hagfish VLRs for use in large scale surveys of the receptor repertoires and to isolate antigen-specific clones for structural and functional characterization. Comparative screening of the VLRA and VLRB libraries for antigen binding will allow us to test the hypothesis that the VLRA and VLRC repertoires are clonally selected for reactivity with processed antigen. Elucidation of the hagfish immune system will help us to understand how and why lymphocyte development along T- and B- cell pathways occurred during vertebrate evolution and to exploit VLRB antibodies for biomedical purposes.

描述（由申请人提供）：盲鳗被广泛认为是当今现存的最基础的脊椎动物，代表着进化的关键点，因此为解开这个谜题提供了关键的一块。我们基于淋巴细胞的适应性免疫系统是如何进化的。最近在两种现存的无颌脊椎动物——七鳃鳗和盲鳗中发现了另一种适应性免疫系统，它们最后一次拥有共同的祖先是在大约 4.8 亿年前。有颌脊椎动物使用基于免疫球蛋白的抗原受体，而无颌脊椎动物则使用三种类型的基于富含亮氨酸重复序列 (LRR) 的可变淋巴细胞受体 (VLR) 来识别抗原。 VLRA 和 VLRC 在相当于七鳃鳗胸腺的鳃区域中由类似于哺乳动物 ab 和 gd T 细胞谱系的两个淋巴细胞谱系组装。 VLRB 由 B 样淋巴细胞在造血组织中组装，B 样淋巴细胞经历浆细胞分化并分泌多价 VLRB 抗体，其结构特征和抗原特异性为生物医学用途提供了显着优势。表达不同 VLR 的盲鳗细胞尚未被鉴定或功能定义。为了阐明盲鳗的免疫系统，专门针对其三个 VLR 的不变部分的单克隆抗体已被用于分析盲鳗淋巴细胞的发育、分布和功能，特别强调确定盲鳗 VLRB 抗体的结构和抗原结合特异性。第一个目标是确定盲鳗 VLRA +、VLRB+ 和 VLRC+ 淋巴细胞的组织分布和基因表达模式。这里的一个主要目标是确定 VLRA 和 VLRB 组装发生的初级位点与成熟淋巴细胞进行增殖和分化的次级位点。第二个目的是表征盲鳗淋巴细胞对抗原、同种异体细胞和有丝分裂原的反应。为了确定为什么盲鳗对免疫表现出较弱的体液免疫反应，但具有丰富的循环 VLRB 蛋白，这些实验将采用精细的免疫方案，在七鳃鳗中引发强烈的 VLRB 抗体反应。初步研究表明盲鳗 VLRA+ 和 VLRC+ 淋巴细胞优先对其他七鳃鳗的细胞作出反应，并提议进行实验来寻找无颌脊椎动物的“同种异体识别元件”。第三个具体目标是构建盲鳗 VLR 的酵母表面展示文库，用于大规模受体库调查，并分离抗原特异性克隆以进行结构和功能表征。对 VLRA 和 VLRB 文库进行抗原结合的比较筛选将使我们能够检验以下假设：VLRA 和 VLRC 库是针对与加工抗原的反应性进行克隆选择的。对盲鳗免疫系统的阐明将帮助我们了解脊椎动物进化过程中淋巴细胞沿着 T 细胞和 B 细胞途径发育的方式和原因，并利用 VLRB 抗体用于生物医学目的。