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Human B1-like Cells and Pneumococcal Defense in the Elderly

人类 B1 样细胞和老年人的肺炎球菌防御

基本信息

批准号：
10553643
负责人：
THOMAS L ROTHSTEIN
金额：
$ 37.75万
依托单位：
WESTERN MICHIGAN UNIV SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-02-01 至 2025-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10553643
关键词：
Address Adoptive Transfer Age Aging Antibodies Antibody Repertoire Antigens Attention B-Lymphocytes Bacteria Binding Biological Assay Cell Count Cell Separation Cell physiology Cell secretion Cells Characteristics Cloning Communicable Diseases Diagnosis Elderly Enzyme-Linked Immunosorbent Assay Failure Flow Cytometry Functional disorder Future Genetic Transcription Human Immune Immune System Diseases Immunity Immunization Immunoglobulin M Immunoglobulins Individual Infection MS4A1 gene Modeling Morbidity - disease rate Mus Nature Organism Performance Persons Phosphorylcholine Pneumococcal Infections Pneumococcal vaccine Population Process Reporting Rest Role Serology Serum Severity of illness Specificity Stains Streptococcus pneumoniae System Time Vaccination Vaccines Work age related enzyme linked immunospot assay experimental study immune function improved in vivo microbial mortality natural antibodies novel therapeutic intervention

项目摘要

The broad, long term objective of this project is to elucidate the mechanism or mechanisms underlying the relative deficiency of serological immunity in the elderly, with particular attention to human B1-like cells and natural antibodies derived therefrom. The specific focus of the present application is to understand the age- related failure of immune defense against infection with S. pneumoniae, both at rest and after immunization with pneumococcal vaccine. A key mechanism for disposing of infectious pneumococci lies in opsonization by serum antibody, and a principal target for opsonizing antibody is phosphorylcholine (PC). Thus, we will study B cells, particularly B1-like cells, that bind PC and secrete anti-PC antibodies. It is known that human serum contains antibodies against PC, that human B1-like cells recognize PC, and that the total population of human B1-like cells declines with age. But it is not known what happens to PC-binding B1-like cells in older individuals as compared to younger individuals. In mice, where adoptive transfer experiments are possible, serum IgM derived from B1 cells of older mice fails to alter the course of pneumococcal infection in mice lacking antibody, whereas an equal amount of serum IgM from younger mice is effective. This coincides with an age-related change in the underlying nature of mouse B1 cell anti- PC antibodies as transcribed immunoglobulin becomes less germline in sequence. These reports regarding age-related changes in total human B1-like cell number and in mouse B1 cell anti-PC antibody repertoire suggest mechanisms for the failure of pneumococcal defense in older people. We hypothesize that the relative deficiency of serological immunity against PC/pneumococci in older humans, before and after pneumococcal vaccination, is due to one or more of: age-related loss of PC- binding B1-like cells, erosion of B1-like cell anti-PC antibody sequence/repertoire, and dysfunction of PC- binding B1-like cells/poor function of B1-like cell anti-PC antibodies. These characteristics have either never been studied in human B1-like cells or never been examined in antigen-specific human B1-like cells with respect to age. We will determine the validity of our hypotheses through the following aims in which we will compare older vs younger healthy donors, and older donors before and after pneumococcal vaccination. SA1. We will evaluate the level of PC-binding B1-like cells, by immunofluorescent staining for B cell subpopulations and PC-binding, followed by flow cytometry/cell sorting. SA2. We will determine the sequence/repertoire of PC-binding B1-like cell antibodies by single cell PCR followed by sequencing, cloning, and ELISA for specificity. SA3. We will evaluate the function of PC-binding B1-like cells and the antibodies they produce, by determining B1-like cell secretion with ELISPOT assays and determining anti- pneumococcal function with opsonophagocytic assays. This work will provide completely new information that will suggest new ways to improve anti-pneumococcal antibody immune defense in the elderly.

这个项目的广泛的长期目标是阐明潜在的机制