Role of the immunoglobulin DQ52 DH gene segment in fetal immunosuppression

免疫球蛋白 DQ52 DH 基因片段在胎儿免疫抑制中的作用

基本信息

批准号：
10451016
负责人：
Harry William Schroeder
金额：
$ 22.28万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-04-01 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10451016
关键词：
Address Adult Affinity Age Amino Acid Sequence Amino Acids Antibodies Antibody Formation Antigens Autoantibodies Autoantigens Autoimmune Diseases Autoimmunity B-Cell Development B-Lymphocytes Birth CAR T cell therapy CRISPR/Cas technology Complementary RNA Complex Consensus Development Disease Elements Embryo Embryonic and Fetal Development Enterobacter cloacae Epitopes Equilibrium Exhibits Fetal Development Fetal Liver Flow Cytometry Generations Genes Genetic Recombination Glycine Goals Growth Growth and Development function Guide RNA Heavy-Chain Immunoglobulins Hen Egg Lysozyme Host resistance Human Immune Immune response Immune system Immunoglobulin Variable Region Immunoglobulins Immunosuppression Inbred BALB C Mice Infection Infectious Agent Knowledge Leucine Life Light Lymphoid Tissue Mature B-Lymphocyte Modeling Mus Neonatal Nucleotides Oocytes Organ Pathogenicity Pattern Peptide/MHC Complex Population Pregnancy Premature Infant Production Reading Frames Regulation Reporting Research Resistance to infection Rest Risk Role Site T-Cell Receptor T-Lymphocyte T-cell receptor repertoire Terminator Codon Testing Tissues Tyrosine V(D)J Recombination autoreactive B cell autoreactivity base cell type combinatorial complementarity-determining region 3 design embryo/fetus fetal immunoglobulin receptor in utero infection risk lymphoid organ mouse model neoantigens preference prenatal progenitor receptor function response secondary lymphoid organ sensor stem cells theories vaccination strategy virtual

项目摘要

Project Summary Our goal is to address the mechanisms that control the humoral immune response during embryonic and fetal development. During ontogeny, the B cells that are needed to populate the various lymphoid tissues and organs sequentially encounter an increasingly complex array of self-antigens as new cell types and non-lymphoid tissues and organs appear. There is a significant risk that embryonic B cells producing potentially pathogenic autoreactive immunoglobulins (Igs) could pass essential developmental checkpoints and thus survive to be activated after these `neo' antigens are ultimately expressed. Unsurprisingly, there is strong evidence that the humoral immune response is selectively suppressed in mammalian embryos and fetuses. Thus, although in theory Ig and T cell receptor (TCR) repertoires appear to be generated in a strictly stochastic fashion through random VDJ rearrangement and N addition; in practice both VDJ rearrangement and N addition are regulated in utero to restrict Ig and TCR diversity. There are 27 functional DH gene segments in humans and 13 in BALB/c mice. We previously showed that VDJ joins from both human and mouse embryonic B cell progenitors were enriched for use of the DQ52 gene segment (D7-27 in human and D4-01 in mouse). After birth, however, both species use DQ52 sparingly. Consequently, regulation of complementarity-determining region 3 of the Ig heavy (H) chain (CDR-H3), which contains the DQ52 gene segment, does not occur by chance and must be a major element of embryonic and early fetal repertoire control. Our prior research has shown that the sequence of the diversity (D) gene segment both delimits the range of CDR diversity and directs, or even dictates, patterns of epitope recognition and antibody production, thereby influencing host resistance to infection and autoimmune disease. DQ52 is the most highly conserved DH between human in mouse. Interestingly, DQ52 differs dramatically in amino acid content from the rest of the Ds, the most striking difference being the absence of tyrosine and enrichment for glycine. In this regard, DQ52 is more similar to TCR Dβ than the other Ig DH, making the in utero DQ52 CDR-H3 repertoire more like TCRβ CDR-B3 than adult Ig CDR-H3. TCRs function more like polyreactive sensors than monospecific effectors. Thus, using DQ52 in CDR-H3 could have the effect of reducing monospecificity and affinity for antigen, and reducing antibody production. These fundamental observations led us to our hypothesis that the role of Ig DQ52 during ontogeny is to promote the production of B cells while simultaneously serving as an immune suppressant DH. To test this hypothesis and to provide proof-of-concept, we propose to (a) use CRISPR/Cas9 technology to create a mouse whose DH locus contains only DQ52 (ΔD-DQ52), (b) test whether use of DQ52 facilitates B cell production, and (c) test whether use of DQ52 results in reduced antibody production. These studies will fill a major gap in our knowledge about the mechanisms that underlie immune suppression of the fetal humoral immune response, which is a major factor in the increased risk of infection in premature infants and in developing in utero vaccination strategies.

项目摘要我们的目标是解决控制胚胎和胎儿期间体液免疫反应的机制发展。在个体发育过程中，填充各种淋巴组织和器官所需的B细胞依次遇到越来越复杂的自我抗原作为新细胞类型和非淋巴机胚胎B细胞产生潜在的致病性有很大的风险自动反应性免疫球蛋白（IGS）可以通过基本的发育检查点，因此生存为在这些“新抗原”之后被激活。毫不奇怪，有充分的证据表明哺乳动物的胚胎和胎儿有选择地抑制体液免疫反应。那，虽然在理论Ig和T细胞受体（TCR）曲目似乎是通过严格的随机方式通过随机VDJ重排和n添加；实际上，VDJ重排和N添加均受到调节子宫限制IG和TCR多样性。人类中有27个功能性DH基因段，BALB/C有13个段老鼠。我们以前表明，VDJ与人类和小鼠胚胎B细胞祖细胞的加入是富集用于使用DQ52基因段（人类中的D7-27和小鼠中的D4-01）。但是，出生后，两者都物种很少使用DQ52。因此，调节Ig重量的互补性区域3 （H）包含DQ52基因段的链（CDR-H3）并非偶然发生，必须是主要的胚胎和早期胎儿曲目控制的元素。我们先前的研究表明，多样性（d）基因段均划定了CDR多样性的范围，并且指示甚至决定了模式表位识别和抗体产生，从而影响宿主对感染和自身免疫性的抗性疾病。 DQ52是小鼠中人之间最高度保守的DH。有趣的是，DQ52有所不同在其余DS的氨基酸含量中，龙是龙，最引人注目的区别是没有甘氨酸的酪氨酸和富集。在这方面，DQ52比其他Ig DH更与TCRDβ相似，使得与成人Ig CDR-H3相比，子宫内DQ52 CDR-H3库更像TCRβCDR-B3。 TCRS功能更像多反应传感器比单特异性效应。那是在CDR-H3中使用DQ52的作用减少对抗原的单特异性和亲和力，并减少抗体产生。这些基本观察结果导致我们假设Ig DQ52在个体发育过程中的作用是促进生产 B细胞的同时作为免疫抑制剂DH。检验这一假设和提供概念验证，我们建议（a）使用CRISPR/CAS9技术创建DH基因座的鼠标仅包含DQ52（ΔD-DQ52），（b）测试DQ52的使用是否促进B细胞的产生，并且（c）测试是否是否测试是否促进 DQ52的使用导致抗体产生降低。这些研究将填补我们对免疫抑制胎儿体液免疫反应的机制，这是主要的因素增加了早产儿和子宫疫苗接种策略中感染风险的增加。